diff options
| author | bors <bors@rust-lang.org> | 2018-03-24 13:23:17 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2018-03-24 13:23:17 +0000 |
| commit | b4aa80dd73df9708022cc383aad8da1dcf38d1df (patch) | |
| tree | 96feb584c23b8680534b22f984fe70834ead5ec2 /src | |
| parent | a0b0f5fba5d7bf18b24d1fa0e454a4fe871fecee (diff) | |
| parent | 94468dac6350a29dc2eb1eed01308ec78224f7ba (diff) | |
| download | rust-b4aa80dd73df9708022cc383aad8da1dcf38d1df.tar.gz rust-b4aa80dd73df9708022cc383aad8da1dcf38d1df.zip | |
Auto merge of #49251 - nikomatsakis:issue-15872-elision-impl-header, r=cramertj
support elision in impl headers
You can now do things like:
```
impl MyTrait<'_> for &u32 { ... }
```
Each `'_` or elided lifetime is a fresh parameter. `'_` and elision are still not permitted in associated type values. (Plausibly we could support that if there is a single input lifetime.) The original lifetime elision RFC was a bit unclear on this point: [as documented here, I think this is the correct interpretation, both because it fits existing impls and it's most analogous to the behavior in fns](https://github.com/rust-lang/rust/issues/15872#issuecomment-338700138).
We do not support elision with deprecated forms:
```
impl MyTrait for std::cell::Ref<u32> { } // ERROR
```
Builds on the in-band lifetime stuff.
r? @cramertj
Fixes #15872
Diffstat (limited to 'src')
20 files changed, 2081 insertions, 1107 deletions
diff --git a/src/librustc/hir/intravisit.rs b/src/librustc/hir/intravisit.rs index 972278bdf86..9f51eb8c35a 100644 --- a/src/librustc/hir/intravisit.rs +++ b/src/librustc/hir/intravisit.rs @@ -420,7 +420,10 @@ pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime LifetimeName::Name(name) => { visitor.visit_name(lifetime.span, name); } - LifetimeName::Static | LifetimeName::Implicit | LifetimeName::Underscore => {} + LifetimeName::Fresh(_) | + LifetimeName::Static | + LifetimeName::Implicit | + LifetimeName::Underscore => {} } } diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index f6bdfde15fc..ad848949f62 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -43,8 +43,8 @@ use dep_graph::DepGraph; use hir; use hir::HirVec; -use hir::map::{Definitions, DefKey, DefPathData}; -use hir::def_id::{DefIndex, DefId, CRATE_DEF_INDEX, DefIndexAddressSpace}; +use hir::map::{DefKey, DefPathData, Definitions}; +use hir::def_id::{DefId, DefIndex, DefIndexAddressSpace, CRATE_DEF_INDEX}; use hir::def::{Def, PathResolution}; use lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES}; use middle::cstore::CrateStore; @@ -63,10 +63,10 @@ use syntax::errors; use syntax::ext::hygiene::{Mark, SyntaxContext}; use syntax::print::pprust; use syntax::ptr::P; -use syntax::codemap::{self, respan, Spanned, CompilerDesugaringKind}; +use syntax::codemap::{self, respan, CompilerDesugaringKind, Spanned}; use syntax::std_inject; -use syntax::symbol::{Symbol, keywords}; -use syntax::tokenstream::{TokenStream, TokenTree, Delimited}; +use syntax::symbol::{keywords, Symbol}; +use syntax::tokenstream::{Delimited, TokenStream, TokenTree}; use syntax::parse::token::Token; use syntax::util::small_vector::SmallVector; use syntax::visit::{self, Visitor}; @@ -80,13 +80,13 @@ pub struct LoweringContext<'a> { // Use to assign ids to hir nodes that do not directly correspond to an ast node sess: &'a Session, - cstore: &'a dyn CrateStore, + cstore: &'a CrateStore, // As we walk the AST we must keep track of the current 'parent' def id (in // the form of a DefIndex) so that if we create a new node which introduces // a definition, then we can properly create the def id. parent_def: Option<DefIndex>, - resolver: &'a mut dyn Resolver, + resolver: &'a mut Resolver, name_map: FxHashMap<Ident, Name>, /// The items being lowered are collected here. @@ -107,6 +107,12 @@ pub struct LoweringContext<'a> { is_in_loop_condition: bool, is_in_trait_impl: bool, + /// What to do when we encounter either an "anonymous lifetime + /// reference". The term "anonymous" is meant to encompass both + /// `'_` lifetimes as well as fully elided cases where nothing is + /// written at all (e.g., `&T` or `std::cell::Ref<T>`). + anonymous_lifetime_mode: AnonymousLifetimeMode, + // This is a list of in-band type definitions being generated by // Argument-position `impl Trait`. // When traversing a signature such as `fn foo(x: impl Trait)`, @@ -121,13 +127,15 @@ pub struct LoweringContext<'a> { // (i.e. it doesn't appear in the in_scope_lifetimes list), it is added // to this list. The results of this list are then added to the list of // lifetime definitions in the corresponding impl or function generics. - lifetimes_to_define: Vec<(Span, Name)>, + lifetimes_to_define: Vec<(Span, hir::LifetimeName)>, + // Whether or not in-band lifetimes are being collected. This is used to // indicate whether or not we're in a place where new lifetimes will result // in in-band lifetime definitions, such a function or an impl header. // This will always be false unless the `in_band_lifetimes` feature is // enabled. is_collecting_in_band_lifetimes: bool, + // Currently in-scope lifetimes defined in impl headers, fn headers, or HRTB. // When `is_collectin_in_band_lifetimes` is true, each lifetime is checked // against this list to see if it is already in-scope, or if a definition @@ -154,8 +162,13 @@ pub trait Resolver { /// Given suffix ["b","c","d"], creates a HIR path for `[::crate_root]::b::c::d` and resolves /// it based on `is_value`. - fn resolve_str_path(&mut self, span: Span, crate_root: Option<&str>, - components: &[&str], is_value: bool) -> hir::Path; + fn resolve_str_path( + &mut self, + span: Span, + crate_root: Option<&str>, + components: &[&str], + is_value: bool, + ) -> hir::Path; } #[derive(Clone, Copy, Debug)] @@ -176,12 +189,13 @@ enum ImplTraitContext { Disallowed, } -pub fn lower_crate(sess: &Session, - cstore: &dyn CrateStore, - dep_graph: &DepGraph, - krate: &Crate, - resolver: &mut dyn Resolver) - -> hir::Crate { +pub fn lower_crate( + sess: &Session, + cstore: &CrateStore, + dep_graph: &DepGraph, + krate: &Crate, + resolver: &mut Resolver, +) -> hir::Crate { // We're constructing the HIR here; we don't care what we will // read, since we haven't even constructed the *input* to // incr. comp. yet. @@ -204,6 +218,7 @@ pub fn lower_crate(sess: &Session, catch_scopes: Vec::new(), loop_scopes: Vec::new(), is_in_loop_condition: false, + anonymous_lifetime_mode: AnonymousLifetimeMode::PassThrough, type_def_lifetime_params: DefIdMap(), current_hir_id_owner: vec![(CRATE_DEF_INDEX, 0)], item_local_id_counters: NodeMap(), @@ -222,7 +237,7 @@ enum ParamMode { /// Any path in a type context. Explicit, /// The `module::Type` in `module::Type::method` in an expression. - Optional + Optional, } struct LoweredNodeId { @@ -236,6 +251,51 @@ enum ParenthesizedGenericArgs { Err, } +/// What to do when we encounter an **anonymous** lifetime +/// reference. Anonymous lifetime references come in two flavors. You +/// have implicit, or fully elided, references to lifetimes, like the +/// one in `&T` or `Ref<T>`, and you have `'_` lifetimes, like `&'_ T` +/// or `Ref<'_, T>`. These often behave the same, but not always: +/// +/// - certain usages of implicit references are deprecated, like +/// `Ref<T>`, and we sometimes just give hard errors in those cases +/// as well. +/// - for object bounds there is a difference: `Box<dyn Foo>` is not +/// the same as `Box<dyn Foo + '_>`. +/// +/// We describe the effects of the various modes in terms of three cases: +/// +/// - **Modern** -- includes all uses of `'_`, but also the lifetime arg +/// of a `&` (e.g., the missing lifetime in something like `&T`) +/// - **Dyn Bound** -- if you have something like `Box<dyn Foo>`, +/// there is an elided lifetime bound (`Box<dyn Foo + 'X>`). These +/// elided bounds follow special rules. Note that this only covers +/// cases where *nothing* is written; the `'_` in `Box<dyn Foo + +/// '_>` is a case of "modern" elision. +/// - **Deprecated** -- this coverse cases like `Ref<T>`, where the lifetime +/// parameter to ref is completely elided. `Ref<'_, T>` would be the modern, +/// non-deprecated equivalent. +/// +/// Currently, the handling of lifetime elision is somewhat spread out +/// between HIR lowering and -- as described below -- the +/// `resolve_lifetime` module. Often we "fallthrough" to that code by generating +/// an "elided" or "underscore" lifetime name. In the future, we probably want to move +/// everything into HIR lowering. +#[derive(Copy, Clone)] +enum AnonymousLifetimeMode { + /// For **Modern** cases, create a new anonymous region parameter + /// and reference that. + /// + /// For **Dyn Bound** cases, pass responsibility to + /// `resolve_lifetime` code. + /// + /// For **Deprecated** cases, report an error. + CreateParameter, + + /// Pass responsibility to `resolve_lifetime` code for all cases. + PassThrough, +} + impl<'a> LoweringContext<'a> { fn lower_crate(mut self, c: &Crate) -> hir::Crate { /// Full-crate AST visitor that inserts into a fresh @@ -252,13 +312,15 @@ impl<'a> LoweringContext<'a> { self.lctx.allocate_hir_id_counter(item.id, item); match item.node { - ItemKind::Struct(_, ref generics) | - ItemKind::Union(_, ref generics) | - ItemKind::Enum(_, ref generics) | - ItemKind::Ty(_, ref generics) | - ItemKind::Trait(_, _, ref generics, ..) => { + ItemKind::Struct(_, ref generics) + | ItemKind::Union(_, ref generics) + | ItemKind::Enum(_, ref generics) + | ItemKind::Ty(_, ref generics) + | ItemKind::Trait(_, _, ref generics, ..) => { let def_id = self.lctx.resolver.definitions().local_def_id(item.id); - let count = generics.params.iter() + let count = generics + .params + .iter() .filter(|param| param.is_lifetime_param()) .count(); self.lctx.type_def_lifetime_params.insert(def_id, count); @@ -285,7 +347,8 @@ impl<'a> LoweringContext<'a> { impl<'lcx, 'interner> ItemLowerer<'lcx, 'interner> { fn with_trait_impl_ref<F>(&mut self, trait_impl_ref: &Option<TraitRef>, f: F) - where F: FnOnce(&mut Self) + where + F: FnOnce(&mut Self), { let old = self.lctx.is_in_trait_impl; self.lctx.is_in_trait_impl = if let &None = trait_impl_ref { @@ -311,22 +374,24 @@ impl<'a> LoweringContext<'a> { if item_lowered { let item_lifetimes = match self.lctx.items.get(&item.id).unwrap().node { - hir::Item_::ItemImpl(_,_,_,ref generics,..) | - hir::Item_::ItemTrait(_,_,ref generics,..) => - generics.lifetimes().cloned().collect::<Vec<_>>(), + hir::Item_::ItemImpl(_, _, _, ref generics, ..) + | hir::Item_::ItemTrait(_, _, ref generics, ..) => { + generics.lifetimes().cloned().collect::<Vec<_>>() + } _ => Vec::new(), }; - self.lctx.with_parent_impl_lifetime_defs(&item_lifetimes, |this| { - let this = &mut ItemLowerer { lctx: this }; - if let ItemKind::Impl(_,_,_,_,ref opt_trait_ref,_,_) = item.node { - this.with_trait_impl_ref(opt_trait_ref, |this| { - visit::walk_item(this, item) - }); - } else { - visit::walk_item(this, item); - } - }); + self.lctx + .with_parent_impl_lifetime_defs(&item_lifetimes, |this| { + let this = &mut ItemLowerer { lctx: this }; + if let ItemKind::Impl(_, _, _, _, ref opt_trait_ref, _, _) = item.node { + this.with_trait_impl_ref(opt_trait_ref, |this| { + visit::walk_item(this, item) + }); + } else { + visit::walk_item(this, item); + } + }); } } @@ -379,27 +444,26 @@ impl<'a> LoweringContext<'a> { } } - fn allocate_hir_id_counter<T: Debug>(&mut self, - owner: NodeId, - debug: &T) { + fn allocate_hir_id_counter<T: Debug>(&mut self, owner: NodeId, debug: &T) { if self.item_local_id_counters.insert(owner, 0).is_some() { - bug!("Tried to allocate item_local_id_counter for {:?} twice", debug); + bug!( + "Tried to allocate item_local_id_counter for {:?} twice", + debug + ); } // Always allocate the first HirId for the owner itself self.lower_node_id_with_owner(owner, owner); } - fn lower_node_id_generic<F>(&mut self, - ast_node_id: NodeId, - alloc_hir_id: F) - -> LoweredNodeId - where F: FnOnce(&mut Self) -> hir::HirId + fn lower_node_id_generic<F>(&mut self, ast_node_id: NodeId, alloc_hir_id: F) -> LoweredNodeId + where + F: FnOnce(&mut Self) -> hir::HirId, { if ast_node_id == DUMMY_NODE_ID { return LoweredNodeId { node_id: DUMMY_NODE_ID, hir_id: hir::DUMMY_HIR_ID, - } + }; } let min_size = ast_node_id.as_usize() + 1; @@ -427,11 +491,12 @@ impl<'a> LoweringContext<'a> { } fn with_hir_id_owner<F>(&mut self, owner: NodeId, f: F) - where F: FnOnce(&mut Self) + where + F: FnOnce(&mut Self), { let counter = self.item_local_id_counters - .insert(owner, HIR_ID_COUNTER_LOCKED) - .unwrap(); + .insert(owner, HIR_ID_COUNTER_LOCKED) + .unwrap(); let def_index = self.resolver.definitions().opt_def_index(owner).unwrap(); self.current_hir_id_owner.push((def_index, counter)); f(self); @@ -440,7 +505,9 @@ impl<'a> LoweringContext<'a> { debug_assert!(def_index == new_def_index); debug_assert!(new_counter >= counter); - let prev = self.item_local_id_counters.insert(owner, new_counter).unwrap(); + let prev = self.item_local_id_counters + .insert(owner, new_counter) + .unwrap(); debug_assert!(prev == HIR_ID_COUNTER_LOCKED); } @@ -452,9 +519,8 @@ impl<'a> LoweringContext<'a> { /// properly. Calling the method twice with the same NodeId is fine though. fn lower_node_id(&mut self, ast_node_id: NodeId) -> LoweredNodeId { self.lower_node_id_generic(ast_node_id, |this| { - let &mut (def_index, ref mut local_id_counter) = this.current_hir_id_owner - .last_mut() - .unwrap(); + let &mut (def_index, ref mut local_id_counter) = + this.current_hir_id_owner.last_mut().unwrap(); let local_id = *local_id_counter; *local_id_counter += 1; hir::HirId { @@ -464,14 +530,9 @@ impl<'a> LoweringContext<'a> { }) } - fn lower_node_id_with_owner(&mut self, - ast_node_id: NodeId, - owner: NodeId) - -> LoweredNodeId { + fn lower_node_id_with_owner(&mut self, ast_node_id: NodeId, owner: NodeId) -> LoweredNodeId { self.lower_node_id_generic(ast_node_id, |this| { - let local_id_counter = this.item_local_id_counters - .get_mut(&owner) - .unwrap(); + let local_id_counter = this.item_local_id_counters.get_mut(&owner).unwrap(); let local_id = *local_id_counter; // We want to be sure not to modify the counter in the map while it @@ -489,8 +550,7 @@ impl<'a> LoweringContext<'a> { }) } - fn record_body(&mut self, value: hir::Expr, decl: Option<&FnDecl>) - -> hir::BodyId { + fn record_body(&mut self, value: hir::Expr, decl: Option<&FnDecl>) -> hir::BodyId { let body = hir::Body { arguments: decl.map_or(hir_vec![], |decl| { decl.inputs.iter().map(|x| self.lower_arg(x)).collect() @@ -524,8 +584,7 @@ impl<'a> LoweringContext<'a> { Symbol::gensym(s) } - fn allow_internal_unstable(&self, reason: CompilerDesugaringKind, span: Span) -> Span - { + fn allow_internal_unstable(&self, reason: CompilerDesugaringKind, span: Span) -> Span { let mark = Mark::fresh(Mark::root()); mark.set_expn_info(codemap::ExpnInfo { call_site: span, @@ -539,73 +598,139 @@ impl<'a> LoweringContext<'a> { span.with_ctxt(SyntaxContext::empty().apply_mark(mark)) } - // Creates a new hir::GenericParam for every new lifetime and type parameter - // encountered while evaluating `f`. Definitions are created with the parent - // provided. If no `parent_id` is provided, no definitions will be returned. + /// Creates a new hir::GenericParam for every new lifetime and + /// type parameter encountered while evaluating `f`. Definitions + /// are created with the parent provided. If no `parent_id` is + /// provided, no definitions will be returned. + /// + /// Presuming that in-band lifetimes are enabled, then + /// `self.anonymous_lifetime_mode` will be updated to match the + /// argument while `f` is running (and restored afterwards). fn collect_in_band_defs<T, F>( &mut self, - parent_id: Option<DefId>, - f: F - ) -> (Vec<hir::GenericParam>, T) where F: FnOnce(&mut LoweringContext) -> T + parent_id: DefId, + anonymous_lifetime_mode: AnonymousLifetimeMode, + f: F, + ) -> (Vec<hir::GenericParam>, T) + where + F: FnOnce(&mut LoweringContext) -> T, { assert!(!self.is_collecting_in_band_lifetimes); assert!(self.lifetimes_to_define.is_empty()); + let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode; + self.is_collecting_in_band_lifetimes = self.sess.features_untracked().in_band_lifetimes; + if self.is_collecting_in_band_lifetimes { + self.anonymous_lifetime_mode = anonymous_lifetime_mode; + } assert!(self.in_band_ty_params.is_empty()); - let res = f(self); self.is_collecting_in_band_lifetimes = false; + self.anonymous_lifetime_mode = old_anonymous_lifetime_mode; let in_band_ty_params = self.in_band_ty_params.split_off(0); let lifetimes_to_define = self.lifetimes_to_define.split_off(0); - let mut params = match parent_id { - Some(parent_id) => lifetimes_to_define.into_iter().map(|(span, name)| { - let def_node_id = self.next_id().node_id; - - // Add a definition for the in-band lifetime def - self.resolver.definitions().create_def_with_parent( - parent_id.index, - def_node_id, - DefPathData::LifetimeDef(name.as_str()), - DefIndexAddressSpace::High, - Mark::root(), - span - ); + let params = lifetimes_to_define + .into_iter() + .map(|(span, hir_name)| { + let def_node_id = self.next_id().node_id; + + // Get the name we'll use to make the def-path. Note + // that collisions are ok here and this shouldn't + // really show up for end-user. + let str_name = match hir_name { + hir::LifetimeName::Name(n) => n.as_str(), + hir::LifetimeName::Fresh(_) => keywords::UnderscoreLifetime.name().as_str(), + hir::LifetimeName::Implicit + | hir::LifetimeName::Underscore + | hir::LifetimeName::Static => { + span_bug!(span, "unexpected in-band lifetime name: {:?}", hir_name) + } + }; - hir::GenericParam::Lifetime(hir::LifetimeDef { - lifetime: hir::Lifetime { - id: def_node_id, - span, - name: hir::LifetimeName::Name(name), - }, - bounds: Vec::new().into(), - pure_wrt_drop: false, - in_band: true, - }) - }).collect(), - None => Vec::new(), - }; + // Add a definition for the in-band lifetime def + self.resolver.definitions().create_def_with_parent( + parent_id.index, + def_node_id, + DefPathData::LifetimeDef(str_name), + DefIndexAddressSpace::High, + Mark::root(), + span, + ); - params.extend(in_band_ty_params.into_iter().map(|tp| hir::GenericParam::Type(tp))); + hir::GenericParam::Lifetime(hir::LifetimeDef { + lifetime: hir::Lifetime { + id: def_node_id, + span, + name: hir_name, + }, + bounds: Vec::new().into(), + pure_wrt_drop: false, + in_band: true, + }) + }) + .chain( + in_band_ty_params + .into_iter() + .map(|tp| hir::GenericParam::Type(tp)), + ) + .collect(); (params, res) } + /// When there is a reference to some lifetime `'a`, and in-band + /// lifetimes are enabled, then we want to push that lifetime into + /// the vector of names to define later. In that case, it will get + /// added to the appropriate generics. + fn maybe_collect_in_band_lifetime(&mut self, span: Span, name: Name) { + if !self.is_collecting_in_band_lifetimes { + return; + } + + if self.in_scope_lifetimes.contains(&name) { + return; + } + + let hir_name = hir::LifetimeName::Name(name); + + if self.lifetimes_to_define + .iter() + .any(|(_, lt_name)| *lt_name == hir_name) + { + return; + } + + self.lifetimes_to_define.push((span, hir_name)); + } + + /// When we have either an elided or `'_` lifetime in an impl + /// header, we convert it to + fn collect_fresh_in_band_lifetime(&mut self, span: Span) -> hir::LifetimeName { + assert!(self.is_collecting_in_band_lifetimes); + let index = self.lifetimes_to_define.len(); + let hir_name = hir::LifetimeName::Fresh(index); + self.lifetimes_to_define.push((span, hir_name)); + hir_name + } + // Evaluates `f` with the lifetimes in `lt_defs` in-scope. // This is used to track which lifetimes have already been defined, and // which are new in-band lifetimes that need to have a definition created // for them. - fn with_in_scope_lifetime_defs<T, F>( + fn with_in_scope_lifetime_defs<'l, T, F>( &mut self, - lt_defs: &[LifetimeDef], - f: F - ) -> T where F: FnOnce(&mut LoweringContext) -> T + lt_defs: impl Iterator<Item = &'l LifetimeDef>, + f: F, + ) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let old_len = self.in_scope_lifetimes.len(); - let lt_def_names = lt_defs.iter().map(|lt_def| lt_def.lifetime.ident.name); + let lt_def_names = lt_defs.map(|lt_def| lt_def.lifetime.ident.name); self.in_scope_lifetimes.extend(lt_def_names); let res = f(self); @@ -619,11 +744,9 @@ impl<'a> LoweringContext<'a> { // This should only be used with generics that have already had their // in-band lifetimes added. In practice, this means that this function is // only used when lowering a child item of a trait or impl. - fn with_parent_impl_lifetime_defs<T, F>( - &mut self, - lt_defs: &[hir::LifetimeDef], - f: F - ) -> T where F: FnOnce(&mut LoweringContext) -> T + fn with_parent_impl_lifetime_defs<T, F>(&mut self, lt_defs: &[hir::LifetimeDef], f: F) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let old_len = self.in_scope_lifetimes.len(); let lt_def_names = lt_defs.iter().map(|lt_def| lt_def.lifetime.name.name()); @@ -635,47 +758,57 @@ impl<'a> LoweringContext<'a> { res } - // Appends in-band lifetime defs and argument-position `impl Trait` defs - // to the existing set of generics. + /// Appends in-band lifetime defs and argument-position `impl + /// Trait` defs to the existing set of generics. + /// + /// Presuming that in-band lifetimes are enabled, then + /// `self.anonymous_lifetime_mode` will be updated to match the + /// argument while `f` is running (and restored afterwards). fn add_in_band_defs<F, T>( &mut self, generics: &Generics, - parent_id: Option<DefId>, - f: F + parent_id: DefId, + anonymous_lifetime_mode: AnonymousLifetimeMode, + f: F, ) -> (hir::Generics, T) - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { - let (in_band_defs, (mut lowered_generics, res)) = - self.with_in_scope_lifetime_defs( - &generics.params - .iter() - .filter_map(|p| match *p { - GenericParam::Lifetime(ref ld) => Some(ld.clone()), - _ => None, - }) - .collect::<Vec<_>>(), - |this| { - this.collect_in_band_defs(parent_id, |this| { - (this.lower_generics(generics), f(this)) - }) - } - ); + let (in_band_defs, (mut lowered_generics, res)) = self.with_in_scope_lifetime_defs( + generics.params.iter().filter_map(|p| match p { + GenericParam::Lifetime(ld) => Some(ld), + _ => None, + }), + |this| { + this.collect_in_band_defs(parent_id, anonymous_lifetime_mode, |this| { + (this.lower_generics(generics), f(this)) + }) + }, + ); - lowered_generics.params = - lowered_generics.params.iter().cloned().chain(in_band_defs).collect(); + lowered_generics.params = lowered_generics + .params + .iter() + .cloned() + .chain(in_band_defs) + .collect(); (lowered_generics, res) } fn with_catch_scope<T, F>(&mut self, catch_id: NodeId, f: F) -> T - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let len = self.catch_scopes.len(); self.catch_scopes.push(catch_id); let result = f(self); - assert_eq!(len + 1, self.catch_scopes.len(), - "catch scopes should be added and removed in stack order"); + assert_eq!( + len + 1, + self.catch_scopes.len(), + "catch scopes should be added and removed in stack order" + ); self.catch_scopes.pop().unwrap(); @@ -683,17 +816,19 @@ impl<'a> LoweringContext<'a> { } fn lower_body<F>(&mut self, decl: Option<&FnDecl>, f: F) -> hir::BodyId - where F: FnOnce(&mut LoweringContext) -> hir::Expr + where + F: FnOnce(&mut LoweringContext) -> hir::Expr, { let prev = mem::replace(&mut self.is_generator, false); let result = f(self); let r = self.record_body(result, decl); self.is_generator = prev; - return r + return r; } fn with_loop_scope<T, F>(&mut self, loop_id: NodeId, f: F) -> T - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { // We're no longer in the base loop's condition; we're in another loop. let was_in_loop_condition = self.is_in_loop_condition; @@ -703,8 +838,11 @@ impl<'a> LoweringContext<'a> { self.loop_scopes.push(loop_id); let result = f(self); - assert_eq!(len + 1, self.loop_scopes.len(), - "Loop scopes should be added and removed in stack order"); + assert_eq!( + len + 1, + self.loop_scopes.len(), + "Loop scopes should be added and removed in stack order" + ); self.loop_scopes.pop().unwrap(); @@ -714,7 +852,8 @@ impl<'a> LoweringContext<'a> { } fn with_loop_condition_scope<T, F>(&mut self, f: F) -> T - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let was_in_loop_condition = self.is_in_loop_condition; self.is_in_loop_condition = true; @@ -727,7 +866,8 @@ impl<'a> LoweringContext<'a> { } fn with_new_scopes<T, F>(&mut self, f: F) -> T - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let was_in_loop_condition = self.is_in_loop_condition; self.is_in_loop_condition = false; @@ -744,7 +884,8 @@ impl<'a> LoweringContext<'a> { } fn with_parent_def<T, F>(&mut self, parent_id: NodeId, f: F) -> T - where F: FnOnce(&mut LoweringContext) -> T + where + F: FnOnce(&mut LoweringContext) -> T, { let old_def = self.parent_def; self.parent_def = { @@ -771,16 +912,19 @@ impl<'a> LoweringContext<'a> { if ident.ctxt == SyntaxContext::empty() { return ident.name; } - *self.name_map.entry(ident).or_insert_with(|| Symbol::from_ident(ident)) + *self.name_map + .entry(ident) + .or_insert_with(|| Symbol::from_ident(ident)) } fn lower_label(&mut self, label: Option<Label>) -> Option<hir::Label> { - label.map(|label| hir::Label { name: label.ident.name, span: label.span }) + label.map(|label| hir::Label { + name: label.ident.name, + span: label.span, + }) } - fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) - -> hir::Destination - { + fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination { match destination { Some((id, label)) => { let target = if let Def::Label(loop_id) = self.expect_full_def(id) { @@ -792,25 +936,31 @@ impl<'a> LoweringContext<'a> { label: self.lower_label(Some(label)), target_id: hir::ScopeTarget::Loop(target), } - }, + } None => { let loop_id = self.loop_scopes - .last() - .map(|innermost_loop_id| *innermost_loop_id); + .last() + .map(|innermost_loop_id| *innermost_loop_id); hir::Destination { label: None, target_id: hir::ScopeTarget::Loop( - loop_id.map(|id| Ok(self.lower_node_id(id).node_id)) - .unwrap_or(Err(hir::LoopIdError::OutsideLoopScope)) - .into()) + loop_id + .map(|id| Ok(self.lower_node_id(id).node_id)) + .unwrap_or(Err(hir::LoopIdError::OutsideLoopScope)) + .into(), + ), } } } } fn lower_attrs(&mut self, attrs: &[Attribute]) -> hir::HirVec<Attribute> { - attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>().into() + attrs + .iter() + .map(|a| self.lower_attr(a)) + .collect::<Vec<_>>() + .into() } fn lower_attr(&mut self, attr: &Attribute) -> Attribute { @@ -825,22 +975,22 @@ impl<'a> LoweringContext<'a> { } fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream { - tokens.into_trees() + tokens + .into_trees() .flat_map(|tree| self.lower_token_tree(tree).into_trees()) .collect() } fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream { match tree { - TokenTree::Token(span, token) => { - self.lower_token(token, span) - } - TokenTree::Delimited(span, delimited) => { - TokenTree::Delimited(span, Delimited { + TokenTree::Token(span, token) => self.lower_token(token, span), + TokenTree::Delimited(span, delimited) => TokenTree::Delimited( + span, + Delimited { delim: delimited.delim, tts: self.lower_token_stream(delimited.tts.into()).into(), - }).into() - } + }, + ).into(), } } @@ -882,27 +1032,25 @@ impl<'a> LoweringContext<'a> { let span = t.span.shrink_to_lo(); let lifetime = match *region { Some(ref lt) => self.lower_lifetime(lt), - None => self.elided_lifetime(span) + None => self.elided_ref_lifetime(span), }; hir::TyRptr(lifetime, self.lower_mt(mt, itctx)) } - TyKind::BareFn(ref f) => { - self.with_in_scope_lifetime_defs( - &f.generic_params - .iter() - .filter_map(|p| match *p { - GenericParam::Lifetime(ref ld) => Some(ld.clone()), - _ => None, - }) - .collect::<Vec<_>>(), - |this| hir::TyBareFn(P(hir::BareFnTy { + TyKind::BareFn(ref f) => self.with_in_scope_lifetime_defs( + f.generic_params.iter().filter_map(|p| match p { + GenericParam::Lifetime(ld) => Some(ld), + _ => None, + }), + |this| { + hir::TyBareFn(P(hir::BareFnTy { generic_params: this.lower_generic_params(&f.generic_params, &NodeMap()), unsafety: this.lower_unsafety(f.unsafety), abi: f.abi, decl: this.lower_fn_decl(&f.decl, None, false), arg_names: this.lower_fn_args_to_names(&f.decl), - }))) - } + })) + }, + ), TyKind::Never => hir::TyNever, TyKind::Tup(ref tys) => { hir::TyTup(tys.iter().map(|ty| self.lower_ty(ty, itctx)).collect()) @@ -919,15 +1067,14 @@ impl<'a> LoweringContext<'a> { } return ty; } - TyKind::ImplicitSelf => { - hir::TyPath(hir::QPath::Resolved(None, P(hir::Path { + TyKind::ImplicitSelf => hir::TyPath(hir::QPath::Resolved( + None, + P(hir::Path { def: self.expect_full_def(t.id), - segments: hir_vec![ - hir::PathSegment::from_name(keywords::SelfType.name()) - ], + segments: hir_vec![hir::PathSegment::from_name(keywords::SelfType.name())], span: t.span, - }))) - } + }), + )), TyKind::Array(ref ty, ref length) => { let length = self.lower_body(None, |this| this.lower_expr(length)); hir::TyArray(self.lower_ty(ty, itctx), length) @@ -938,8 +1085,9 @@ impl<'a> LoweringContext<'a> { } TyKind::TraitObject(ref bounds, kind) => { let mut lifetime_bound = None; - let bounds = bounds.iter().filter_map(|bound| { - match *bound { + let bounds = bounds + .iter() + .filter_map(|bound| match *bound { TraitTyParamBound(ref ty, TraitBoundModifier::None) => { Some(self.lower_poly_trait_ref(ty, itctx)) } @@ -950,11 +1098,10 @@ impl<'a> LoweringContext<'a> { } None } - } - }).collect(); - let lifetime_bound = lifetime_bound.unwrap_or_else(|| { - self.elided_lifetime(t.span) - }); + }) + .collect(); + let lifetime_bound = + lifetime_bound.unwrap_or_else(|| self.elided_dyn_bound(t.span)); if kind != TraitObjectSyntax::Dyn { self.maybe_lint_bare_trait(t.span, t.id, false); } @@ -967,33 +1114,44 @@ impl<'a> LoweringContext<'a> { ImplTraitContext::Existential => { let has_feature = self.sess.features_untracked().conservative_impl_trait; if !t.span.allows_unstable() && !has_feature { - emit_feature_err(&self.sess.parse_sess, "conservative_impl_trait", - t.span, GateIssue::Language, - "`impl Trait` in return position is experimental"); + emit_feature_err( + &self.sess.parse_sess, + "conservative_impl_trait", + t.span, + GateIssue::Language, + "`impl Trait` in return position is experimental", + ); } let def_index = self.resolver.definitions().opt_def_index(t.id).unwrap(); let hir_bounds = self.lower_bounds(bounds, itctx); let (lifetimes, lifetime_defs) = self.lifetimes_from_impl_trait_bounds(def_index, &hir_bounds); - hir::TyImplTraitExistential(hir::ExistTy { - generics: hir::Generics { - params: lifetime_defs, - where_clause: hir::WhereClause { - id: self.next_id().node_id, - predicates: Vec::new().into(), + hir::TyImplTraitExistential( + hir::ExistTy { + generics: hir::Generics { + params: lifetime_defs, + where_clause: hir::WhereClause { + id: self.next_id().node_id, + predicates: Vec::new().into(), + }, + span, }, - span, + bounds: hir_bounds, }, - bounds: hir_bounds, - }, lifetimes) - }, + lifetimes, + ) + } ImplTraitContext::Universal(def_id) => { let has_feature = self.sess.features_untracked().universal_impl_trait; if !t.span.allows_unstable() && !has_feature { - emit_feature_err(&self.sess.parse_sess, "universal_impl_trait", - t.span, GateIssue::Language, - "`impl Trait` in argument position is experimental"); + emit_feature_err( + &self.sess.parse_sess, + "universal_impl_trait", + t.span, + GateIssue::Language, + "`impl Trait` in argument position is experimental", + ); } let def_node_id = self.next_id().node_id; @@ -1005,7 +1163,7 @@ impl<'a> LoweringContext<'a> { DefPathData::ImplTrait, DefIndexAddressSpace::High, Mark::root(), - span + span, ); let hir_bounds = self.lower_bounds(bounds, itctx); @@ -1022,16 +1180,23 @@ impl<'a> LoweringContext<'a> { attrs: P::new(), }); - hir::TyPath(hir::QPath::Resolved(None, P(hir::Path { - span, - def: Def::TyParam(DefId::local(def_index)), - segments: hir_vec![hir::PathSegment::from_name(name)], - }))) - }, + hir::TyPath(hir::QPath::Resolved( + None, + P(hir::Path { + span, + def: Def::TyParam(DefId::local(def_index)), + segments: hir_vec![hir::PathSegment::from_name(name)], + }), + )) + } ImplTraitContext::Disallowed => { - span_err!(self.sess, t.span, E0562, - "`impl Trait` not allowed outside of function \ - and inherent method return types"); + span_err!( + self.sess, + t.span, + E0562, + "`impl Trait` not allowed outside of function \ + and inherent method return types" + ); hir::TyErr } } @@ -1051,9 +1216,8 @@ impl<'a> LoweringContext<'a> { fn lifetimes_from_impl_trait_bounds( &mut self, parent_index: DefIndex, - bounds: &hir::TyParamBounds + bounds: &hir::TyParamBounds, ) -> (HirVec<hir::Lifetime>, HirVec<hir::GenericParam>) { - // This visitor walks over impl trait bounds and creates defs for all lifetimes which // appear in the bounds, excluding lifetimes that are created within the bounds. // e.g. 'a, 'b, but not 'c in `impl for<'c> SomeTrait<'a, 'b, 'c>` @@ -1068,8 +1232,9 @@ impl<'a> LoweringContext<'a> { } impl<'r, 'a: 'r, 'v> hir::intravisit::Visitor<'v> for ImplTraitLifetimeCollector<'r, 'a> { - fn nested_visit_map<'this>(&'this mut self) - -> hir::intravisit::NestedVisitorMap<'this, 'v> { + fn nested_visit_map<'this>( + &'this mut self, + ) -> hir::intravisit::NestedVisitorMap<'this, 'v> { hir::intravisit::NestedVisitorMap::None } @@ -1097,9 +1262,11 @@ impl<'a> LoweringContext<'a> { } } - fn visit_poly_trait_ref(&mut self, - polytr: &'v hir::PolyTraitRef, - _: hir::TraitBoundModifier) { + fn visit_poly_trait_ref( + &mut self, + polytr: &'v hir::PolyTraitRef, + _: hir::TraitBoundModifier, + ) { let old_len = self.currently_bound_lifetimes.len(); // Record the introduction of 'a in `for<'a> ...` @@ -1123,21 +1290,22 @@ impl<'a> LoweringContext<'a> { fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) { let name = match lifetime.name { - hir::LifetimeName::Implicit | - hir::LifetimeName::Underscore => + hir::LifetimeName::Implicit | hir::LifetimeName::Underscore => { if self.collect_elided_lifetimes { // Use `'_` for both implicit and underscore lifetimes in // `abstract type Foo<'_>: SomeTrait<'_>;` hir::LifetimeName::Underscore } else { - return + return; } + } + name @ hir::LifetimeName::Fresh(_) => name, name @ hir::LifetimeName::Name(_) => name, hir::LifetimeName::Static => return, }; - if !self.currently_bound_lifetimes.contains(&name) && - !self.already_defined_lifetimes.contains(&name) + if !self.currently_bound_lifetimes.contains(&name) + && !self.already_defined_lifetimes.contains(&name) { self.already_defined_lifetimes.insert(name); @@ -1154,19 +1322,20 @@ impl<'a> LoweringContext<'a> { DefPathData::LifetimeDef(name.name().as_str()), DefIndexAddressSpace::High, Mark::root(), - lifetime.span + lifetime.span, ); let def_lifetime = hir::Lifetime { id: def_node_id, span: lifetime.span, name: name, }; - self.output_lifetime_params.push(hir::GenericParam::Lifetime(hir::LifetimeDef { - lifetime: def_lifetime, - bounds: Vec::new().into(), - pure_wrt_drop: false, - in_band: false, - })); + self.output_lifetime_params + .push(hir::GenericParam::Lifetime(hir::LifetimeDef { + lifetime: def_lifetime, + bounds: Vec::new().into(), + pure_wrt_drop: false, + in_band: false, + })); } } } @@ -1187,14 +1356,17 @@ impl<'a> LoweringContext<'a> { ( lifetime_collector.output_lifetimes.into(), - lifetime_collector.output_lifetime_params.into() + lifetime_collector.output_lifetime_params.into(), ) } fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod { hir::ForeignMod { abi: fm.abi, - items: fm.items.iter().map(|x| self.lower_foreign_item(x)).collect(), + items: fm.items + .iter() + .map(|x| self.lower_foreign_item(x)) + .collect(), } } @@ -1211,94 +1383,116 @@ impl<'a> LoweringContext<'a> { name: v.node.name.name, attrs: self.lower_attrs(&v.node.attrs), data: self.lower_variant_data(&v.node.data), - disr_expr: v.node.disr_expr.as_ref().map(|e| { - self.lower_body(None, |this| this.lower_expr(e)) - }), + disr_expr: v.node + .disr_expr + .as_ref() + .map(|e| self.lower_body(None, |this| this.lower_expr(e))), }, span: v.span, } } - fn lower_qpath(&mut self, - id: NodeId, - qself: &Option<QSelf>, - p: &Path, - param_mode: ParamMode, - itctx: ImplTraitContext) - -> hir::QPath { + fn lower_qpath( + &mut self, + id: NodeId, + qself: &Option<QSelf>, + p: &Path, + param_mode: ParamMode, + itctx: ImplTraitContext, + ) -> hir::QPath { let qself_position = qself.as_ref().map(|q| q.position); let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx)); - let resolution = self.resolver.get_resolution(id) - .unwrap_or(PathResolution::new(Def::Err)); + let resolution = self.resolver + .get_resolution(id) + .unwrap_or(PathResolution::new(Def::Err)); let proj_start = p.segments.len() - resolution.unresolved_segments(); let path = P(hir::Path { def: resolution.base_def(), - segments: p.segments[..proj_start].iter().enumerate().map(|(i, segment)| { - let param_mode = match (qself_position, param_mode) { - (Some(j), ParamMode::Optional) if i < j => { - // This segment is part of the trait path in a - // qualified path - one of `a`, `b` or `Trait` - // in `<X as a::b::Trait>::T::U::method`. - ParamMode::Explicit - } - _ => param_mode - }; + segments: p.segments[..proj_start] + .iter() + .enumerate() + .map(|(i, segment)| { + let param_mode = match (qself_position, param_mode) { + (Some(j), ParamMode::Optional) if i < j => { + // This segment is part of the trait path in a + // qualified path - one of `a`, `b` or `Trait` + // in `<X as a::b::Trait>::T::U::method`. + ParamMode::Explicit + } + _ => param_mode, + }; - // Figure out if this is a type/trait segment, - // which may need lifetime elision performed. - let parent_def_id = |this: &mut Self, def_id: DefId| { - DefId { + // Figure out if this is a type/trait segment, + // which may need lifetime elision performed. + let parent_def_id = |this: &mut Self, def_id: DefId| DefId { krate: def_id.krate, - index: this.def_key(def_id).parent.expect("missing parent") - } - }; - let type_def_id = match resolution.base_def() { - Def::AssociatedTy(def_id) if i + 2 == proj_start => { - Some(parent_def_id(self, def_id)) - } - Def::Variant(def_id) if i + 1 == proj_start => { - Some(parent_def_id(self, def_id)) - } - Def::Struct(def_id) | - Def::Union(def_id) | - Def::Enum(def_id) | - Def::TyAlias(def_id) | - Def::Trait(def_id) if i + 1 == proj_start => Some(def_id), - _ => None - }; - let parenthesized_generic_args = match resolution.base_def() { - // `a::b::Trait(Args)` - Def::Trait(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Ok, - // `a::b::Trait(Args)::TraitItem` - Def::Method(..) | - Def::AssociatedConst(..) | - Def::AssociatedTy(..) if i + 2 == proj_start => ParenthesizedGenericArgs::Ok, - // Avoid duplicated errors - Def::Err => ParenthesizedGenericArgs::Ok, - // An error - Def::Struct(..) | Def::Enum(..) | Def::Union(..) | Def::TyAlias(..) | - Def::Variant(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Err, - // A warning for now, for compatibility reasons - _ => ParenthesizedGenericArgs::Warn, - }; + index: this.def_key(def_id).parent.expect("missing parent"), + }; + let type_def_id = match resolution.base_def() { + Def::AssociatedTy(def_id) if i + 2 == proj_start => { + Some(parent_def_id(self, def_id)) + } + Def::Variant(def_id) if i + 1 == proj_start => { + Some(parent_def_id(self, def_id)) + } + Def::Struct(def_id) + | Def::Union(def_id) + | Def::Enum(def_id) + | Def::TyAlias(def_id) + | Def::Trait(def_id) if i + 1 == proj_start => + { + Some(def_id) + } + _ => None, + }; + let parenthesized_generic_args = match resolution.base_def() { + // `a::b::Trait(Args)` + Def::Trait(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Ok, + // `a::b::Trait(Args)::TraitItem` + Def::Method(..) | Def::AssociatedConst(..) | Def::AssociatedTy(..) + if i + 2 == proj_start => + { + ParenthesizedGenericArgs::Ok + } + // Avoid duplicated errors + Def::Err => ParenthesizedGenericArgs::Ok, + // An error + Def::Struct(..) + | Def::Enum(..) + | Def::Union(..) + | Def::TyAlias(..) + | Def::Variant(..) if i + 1 == proj_start => + { + ParenthesizedGenericArgs::Err + } + // A warning for now, for compatibility reasons + _ => ParenthesizedGenericArgs::Warn, + }; - let num_lifetimes = type_def_id.map_or(0, |def_id| { - if let Some(&n) = self.type_def_lifetime_params.get(&def_id) { - return n; - } - assert!(!def_id.is_local()); - let n = self.cstore - .item_generics_cloned_untracked(def_id, self.sess) - .regions - .len(); - self.type_def_lifetime_params.insert(def_id, n); - n - }); - self.lower_path_segment(p.span, segment, param_mode, num_lifetimes, - parenthesized_generic_args, itctx) - }).collect(), + let num_lifetimes = type_def_id.map_or(0, |def_id| { + if let Some(&n) = self.type_def_lifetime_params.get(&def_id) { + return n; + } + assert!(!def_id.is_local()); + let n = self.cstore + .item_generics_cloned_untracked(def_id, self.sess) + .regions + .len(); + self.type_def_lifetime_params.insert(def_id, n); + n + }); + self.lower_path_segment( + p.span, + segment, + param_mode, + num_lifetimes, + parenthesized_generic_args, + itctx, + ) + }) + .collect(), span: p.span, }); @@ -1332,9 +1526,14 @@ impl<'a> LoweringContext<'a> { // 3. `<<std::vec::Vec<T>>::IntoIter>::Item` // * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone` for (i, segment) in p.segments.iter().enumerate().skip(proj_start) { - let segment = P(self.lower_path_segment(p.span, segment, param_mode, 0, - ParenthesizedGenericArgs::Warn, - itctx)); + let segment = P(self.lower_path_segment( + p.span, + segment, + param_mode, + 0, + ParenthesizedGenericArgs::Warn, + itctx, + )); let qpath = hir::QPath::TypeRelative(ty, segment); // It's finished, return the extension of the right node type. @@ -1348,44 +1547,54 @@ impl<'a> LoweringContext<'a> { } // Should've returned in the for loop above. - span_bug!(p.span, "lower_qpath: no final extension segment in {}..{}", - proj_start, p.segments.len()) + span_bug!( + p.span, + "lower_qpath: no final extension segment in {}..{}", + proj_start, + p.segments.len() + ) } - fn lower_path_extra(&mut self, - id: NodeId, - p: &Path, - name: Option<Name>, - param_mode: ParamMode) - -> hir::Path { + fn lower_path_extra( + &mut self, + id: NodeId, + p: &Path, + name: Option<Name>, + param_mode: ParamMode, + ) -> hir::Path { hir::Path { def: self.expect_full_def(id), - segments: p.segments.iter().map(|segment| { - self.lower_path_segment(p.span, segment, param_mode, 0, - ParenthesizedGenericArgs::Err, - ImplTraitContext::Disallowed) - }).chain(name.map(|name| hir::PathSegment::from_name(name))) - .collect(), + segments: p.segments + .iter() + .map(|segment| { + self.lower_path_segment( + p.span, + segment, + param_mode, + 0, + ParenthesizedGenericArgs::Err, + ImplTraitContext::Disallowed, + ) + }) + .chain(name.map(|name| hir::PathSegment::from_name(name))) + .collect(), span: p.span, } } - fn lower_path(&mut self, - id: NodeId, - p: &Path, - param_mode: ParamMode) - -> hir::Path { + fn lower_path(&mut self, id: NodeId, p: &Path, param_mode: ParamMode) -> hir::Path { self.lower_path_extra(id, p, None, param_mode) } - fn lower_path_segment(&mut self, - path_span: Span, - segment: &PathSegment, - param_mode: ParamMode, - expected_lifetimes: usize, - parenthesized_generic_args: ParenthesizedGenericArgs, - itctx: ImplTraitContext) - -> hir::PathSegment { + fn lower_path_segment( + &mut self, + path_span: Span, + segment: &PathSegment, + param_mode: ParamMode, + expected_lifetimes: usize, + parenthesized_generic_args: ParenthesizedGenericArgs, + itctx: ImplTraitContext, + ) -> hir::PathSegment { let (mut parameters, infer_types) = if let Some(ref parameters) = segment.parameters { let msg = "parenthesized parameters may only be used with a trait"; match **parameters { @@ -1393,74 +1602,108 @@ impl<'a> LoweringContext<'a> { self.lower_angle_bracketed_parameter_data(data, param_mode, itctx) } PathParameters::Parenthesized(ref data) => match parenthesized_generic_args { - ParenthesizedGenericArgs::Ok => - self.lower_parenthesized_parameter_data(data), + ParenthesizedGenericArgs::Ok => self.lower_parenthesized_parameter_data(data), ParenthesizedGenericArgs::Warn => { - self.sess.buffer_lint(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES, - CRATE_NODE_ID, data.span, msg.into()); + self.sess.buffer_lint( + PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES, + CRATE_NODE_ID, + data.span, + msg.into(), + ); (hir::PathParameters::none(), true) } ParenthesizedGenericArgs::Err => { struct_span_err!(self.sess, data.span, E0214, "{}", msg) - .span_label(data.span, "only traits may use parentheses").emit(); + .span_label(data.span, "only traits may use parentheses") + .emit(); (hir::PathParameters::none(), true) } - } + }, } } else { self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode, itctx) }; if !parameters.parenthesized && parameters.lifetimes.is_empty() { - parameters.lifetimes = (0..expected_lifetimes).map(|_| { - self.elided_lifetime(path_span) - }).collect(); + parameters.lifetimes = self.elided_path_lifetimes(path_span, expected_lifetimes); } hir::PathSegment::new( self.lower_ident(segment.identifier), parameters, - infer_types + infer_types, ) } - fn lower_angle_bracketed_parameter_data(&mut self, - data: &AngleBracketedParameterData, - param_mode: ParamMode, - itctx: ImplTraitContext) - -> (hir::PathParameters, bool) { - let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings, .. } = data; - (hir::PathParameters { - lifetimes: self.lower_lifetimes(lifetimes), - types: types.iter().map(|ty| self.lower_ty(ty, itctx)).collect(), - bindings: bindings.iter().map(|b| self.lower_ty_binding(b, itctx)).collect(), - parenthesized: false, - }, types.is_empty() && param_mode == ParamMode::Optional) + fn lower_angle_bracketed_parameter_data( + &mut self, + data: &AngleBracketedParameterData, + param_mode: ParamMode, + itctx: ImplTraitContext, + ) -> (hir::PathParameters, bool) { + let &AngleBracketedParameterData { + ref lifetimes, + ref types, + ref bindings, + .. + } = data; + ( + hir::PathParameters { + lifetimes: self.lower_lifetimes(lifetimes), + types: types.iter().map(|ty| self.lower_ty(ty, itctx)).collect(), + bindings: bindings + .iter() + .map(|b| self.lower_ty_binding(b, itctx)) + .collect(), + parenthesized: false, + }, + types.is_empty() && param_mode == ParamMode::Optional, + ) } - fn lower_parenthesized_parameter_data(&mut self, - data: &ParenthesizedParameterData) - -> (hir::PathParameters, bool) { + fn lower_parenthesized_parameter_data( + &mut self, + data: &ParenthesizedParameterData, + ) -> (hir::PathParameters, bool) { const DISALLOWED: ImplTraitContext = ImplTraitContext::Disallowed; - let &ParenthesizedParameterData { ref inputs, ref output, span } = data; - let inputs = inputs.iter().map(|ty| self.lower_ty(ty, DISALLOWED)).collect(); + let &ParenthesizedParameterData { + ref inputs, + ref output, + span, + } = data; + let inputs = inputs + .iter() + .map(|ty| self.lower_ty(ty, DISALLOWED)) + .collect(); let mk_tup = |this: &mut Self, tys, span| { let LoweredNodeId { node_id, hir_id } = this.next_id(); - P(hir::Ty { node: hir::TyTup(tys), id: node_id, hir_id, span }) + P(hir::Ty { + node: hir::TyTup(tys), + id: node_id, + hir_id, + span, + }) }; - (hir::PathParameters { - lifetimes: hir::HirVec::new(), - types: hir_vec![mk_tup(self, inputs, span)], - bindings: hir_vec![hir::TypeBinding { - id: self.next_id().node_id, - name: Symbol::intern(FN_OUTPUT_NAME), - ty: output.as_ref().map(|ty| self.lower_ty(&ty, DISALLOWED)) - .unwrap_or_else(|| mk_tup(self, hir::HirVec::new(), span)), - span: output.as_ref().map_or(span, |ty| ty.span), - }], - parenthesized: true, - }, false) + ( + hir::PathParameters { + lifetimes: hir::HirVec::new(), + types: hir_vec![mk_tup(self, inputs, span)], + bindings: hir_vec![ + hir::TypeBinding { + id: self.next_id().node_id, + name: Symbol::intern(FN_OUTPUT_NAME), + ty: output + .as_ref() + .map(|ty| self.lower_ty(&ty, DISALLOWED)) + .unwrap_or_else(|| mk_tup(self, hir::HirVec::new(), span)), + span: output.as_ref().map_or(span, |ty| ty.span), + } + ], + parenthesized: true, + }, + false, + ) } fn lower_local(&mut self, l: &Local) -> P<hir::Local> { @@ -1468,7 +1711,9 @@ impl<'a> LoweringContext<'a> { P(hir::Local { id: node_id, hir_id, - ty: l.ty.as_ref().map(|t| self.lower_ty(t, ImplTraitContext::Disallowed)), + ty: l.ty + .as_ref() + .map(|t| self.lower_ty(t, ImplTraitContext::Disallowed)), pat: self.lower_pat(&l.pat), init: l.init.as_ref().map(|e| P(self.lower_expr(e))), span: l.span, @@ -1493,24 +1738,22 @@ impl<'a> LoweringContext<'a> { } } - fn lower_fn_args_to_names(&mut self, decl: &FnDecl) - -> hir::HirVec<Spanned<Name>> { - decl.inputs.iter().map(|arg| { - match arg.pat.node { - PatKind::Ident(_, ident, None) => { - respan(ident.span, ident.node.name) - } + fn lower_fn_args_to_names(&mut self, decl: &FnDecl) -> hir::HirVec<Spanned<Name>> { + decl.inputs + .iter() + .map(|arg| match arg.pat.node { + PatKind::Ident(_, ident, None) => respan(ident.span, ident.node.name), _ => respan(arg.pat.span, keywords::Invalid.name()), - } - }).collect() + }) + .collect() } - - fn lower_fn_decl(&mut self, - decl: &FnDecl, - fn_def_id: Option<DefId>, - impl_trait_return_allow: bool) - -> P<hir::FnDecl> { + fn lower_fn_decl( + &mut self, + decl: &FnDecl, + fn_def_id: Option<DefId>, + impl_trait_return_allow: bool, + ) -> P<hir::FnDecl> { // NOTE: The two last parameters here have to do with impl Trait. If fn_def_id is Some, // then impl Trait arguments are lowered into generic parameters on the given // fn_def_id, otherwise impl Trait is disallowed. (for now) @@ -1519,38 +1762,44 @@ impl<'a> LoweringContext<'a> { // return positions as well. This guards against trait declarations and their impls // where impl Trait is disallowed. (again for now) P(hir::FnDecl { - inputs: decl.inputs.iter() - .map(|arg| if let Some(def_id) = fn_def_id { - self.lower_ty(&arg.ty, ImplTraitContext::Universal(def_id)) - } else { - self.lower_ty(&arg.ty, ImplTraitContext::Disallowed) - }).collect(), + inputs: decl.inputs + .iter() + .map(|arg| { + if let Some(def_id) = fn_def_id { + self.lower_ty(&arg.ty, ImplTraitContext::Universal(def_id)) + } else { + self.lower_ty(&arg.ty, ImplTraitContext::Disallowed) + } + }) + .collect(), output: match decl.output { FunctionRetTy::Ty(ref ty) => match fn_def_id { - Some(_) if impl_trait_return_allow => - hir::Return(self.lower_ty(ty, ImplTraitContext::Existential)), + Some(_) if impl_trait_return_allow => { + hir::Return(self.lower_ty(ty, ImplTraitContext::Existential)) + } _ => hir::Return(self.lower_ty(ty, ImplTraitContext::Disallowed)), }, FunctionRetTy::Default(span) => hir::DefaultReturn(span), }, variadic: decl.variadic, - has_implicit_self: decl.inputs.get(0).map_or(false, |arg| { - match arg.ty.node { - TyKind::ImplicitSelf => true, - TyKind::Rptr(_, ref mt) => mt.ty.node == TyKind::ImplicitSelf, - _ => false - } - }) + has_implicit_self: decl.inputs.get(0).map_or(false, |arg| match arg.ty.node { + TyKind::ImplicitSelf => true, + TyKind::Rptr(_, ref mt) => mt.ty.node == TyKind::ImplicitSelf, + _ => false, + }), }) } - fn lower_ty_param_bound(&mut self, tpb: &TyParamBound, itctx: ImplTraitContext) - -> hir::TyParamBound { + fn lower_ty_param_bound( + &mut self, + tpb: &TyParamBound, + itctx: ImplTraitContext, + ) -> hir::TyParamBound { match *tpb { - TraitTyParamBound(ref ty, modifier) => { - hir::TraitTyParamBound(self.lower_poly_trait_ref(ty, itctx), - self.lower_trait_bound_modifier(modifier)) - } + TraitTyParamBound(ref ty, modifier) => hir::TraitTyParamBound( + self.lower_poly_trait_ref(ty, itctx), + self.lower_trait_bound_modifier(modifier), + ), RegionTyParamBound(ref lifetime) => { hir::RegionTyParamBound(self.lower_lifetime(lifetime)) } @@ -1570,48 +1819,60 @@ impl<'a> LoweringContext<'a> { let itctx = ImplTraitContext::Universal(self.resolver.definitions().local_def_id(tp.id)); let mut bounds = self.lower_bounds(&tp.bounds, itctx); if !add_bounds.is_empty() { - bounds = bounds.into_iter().chain( - self.lower_bounds(add_bounds, itctx).into_iter() - ).collect(); + bounds = bounds + .into_iter() + .chain(self.lower_bounds(add_bounds, itctx).into_iter()) + .collect(); } hir::TyParam { id: self.lower_node_id(tp.id).node_id, name, bounds, - default: tp.default.as_ref().map(|x| self.lower_ty(x, ImplTraitContext::Disallowed)), + default: tp.default + .as_ref() + .map(|x| self.lower_ty(x, ImplTraitContext::Disallowed)), span: tp.span, pure_wrt_drop: attr::contains_name(&tp.attrs, "may_dangle"), - synthetic: tp.attrs.iter() - .filter(|attr| attr.check_name("rustc_synthetic")) - .map(|_| hir::SyntheticTyParamKind::ImplTrait) - .nth(0), + synthetic: tp.attrs + .iter() + .filter(|attr| attr.check_name("rustc_synthetic")) + .map(|_| hir::SyntheticTyParamKind::ImplTrait) + .nth(0), attrs: self.lower_attrs(&tp.attrs), } } fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime { - let name = match self.lower_ident(l.ident) { - x if x == "'_" => hir::LifetimeName::Underscore, - x if x == "'static" => hir::LifetimeName::Static, - name => { - if self.is_collecting_in_band_lifetimes && - !self.in_scope_lifetimes.contains(&name) && - self.lifetimes_to_define.iter() - .find(|&&(_, lt_name)| lt_name == name) - .is_none() - { - self.lifetimes_to_define.push((l.span, name)); + match self.lower_ident(l.ident) { + x if x == "'static" => self.new_named_lifetime(l.id, l.span, hir::LifetimeName::Static), + x if x == "'_" => match self.anonymous_lifetime_mode { + AnonymousLifetimeMode::CreateParameter => { + let fresh_name = self.collect_fresh_in_band_lifetime(l.span); + self.new_named_lifetime(l.id, l.span, fresh_name) } - hir::LifetimeName::Name(name) + AnonymousLifetimeMode::PassThrough => { + self.new_named_lifetime(l.id, l.span, hir::LifetimeName::Underscore) + } + }, + name => { + self.maybe_collect_in_band_lifetime(l.span, name); + self.new_named_lifetime(l.id, l.span, hir::LifetimeName::Name(name)) } - }; + } + } + fn new_named_lifetime( + &mut self, + id: NodeId, + span: Span, + name: hir::LifetimeName, + ) -> hir::Lifetime { hir::Lifetime { - id: self.lower_node_id(l.id).node_id, - name, - span: l.span, + id: self.lower_node_id(id).node_id, + span, + name: name, } } @@ -1640,17 +1901,16 @@ impl<'a> LoweringContext<'a> { params: &Vec<GenericParam>, add_bounds: &NodeMap<Vec<TyParamBound>>, ) -> hir::HirVec<hir::GenericParam> { - params.iter() + params + .iter() .map(|param| match *param { GenericParam::Lifetime(ref lifetime_def) => { hir::GenericParam::Lifetime(self.lower_lifetime_def(lifetime_def)) } - GenericParam::Type(ref ty_param) => { - hir::GenericParam::Type(self.lower_ty_param( - ty_param, - add_bounds.get(&ty_param.id).map_or(&[][..], |x| &x) - )) - } + GenericParam::Type(ref ty_param) => hir::GenericParam::Type(self.lower_ty_param( + ty_param, + add_bounds.get(&ty_param.id).map_or(&[][..], |x| &x), + )), }) .collect() } @@ -1666,24 +1926,30 @@ impl<'a> LoweringContext<'a> { 'next_bound: for bound in &bound_pred.bounds { if let TraitTyParamBound(_, TraitBoundModifier::Maybe) = *bound { let report_error = |this: &mut Self| { - this.diagnostic().span_err(bound_pred.bounded_ty.span, - "`?Trait` bounds are only permitted at the \ - point where a type parameter is declared"); + this.diagnostic().span_err( + bound_pred.bounded_ty.span, + "`?Trait` bounds are only permitted at the \ + point where a type parameter is declared", + ); }; // Check if the where clause type is a plain type parameter. match bound_pred.bounded_ty.node { TyKind::Path(None, ref path) - if path.segments.len() == 1 && - bound_pred.bound_generic_params.is_empty() => { - if let Some(Def::TyParam(def_id)) = - self.resolver.get_resolution(bound_pred.bounded_ty.id) - .map(|d| d.base_def()) { + if path.segments.len() == 1 + && bound_pred.bound_generic_params.is_empty() => + { + if let Some(Def::TyParam(def_id)) = self.resolver + .get_resolution(bound_pred.bounded_ty.id) + .map(|d| d.base_def()) + { if let Some(node_id) = - self.resolver.definitions().as_local_node_id(def_id) { + self.resolver.definitions().as_local_node_id(def_id) + { for param in &g.params { if let GenericParam::Type(ref ty_param) = *param { if node_id == ty_param.id { - add_bounds.entry(ty_param.id) + add_bounds + .entry(ty_param.id) .or_insert(Vec::new()) .push(bound.clone()); continue 'next_bound; @@ -1694,7 +1960,7 @@ impl<'a> LoweringContext<'a> { } report_error(self) } - _ => report_error(self) + _ => report_error(self), } } } @@ -1712,81 +1978,93 @@ impl<'a> LoweringContext<'a> { hir::WhereClause { id: self.lower_node_id(wc.id).node_id, predicates: wc.predicates - .iter() - .map(|predicate| self.lower_where_predicate(predicate)) - .collect(), + .iter() + .map(|predicate| self.lower_where_predicate(predicate)) + .collect(), } } fn lower_where_predicate(&mut self, pred: &WherePredicate) -> hir::WherePredicate { match *pred { - WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_generic_params, - ref bounded_ty, - ref bounds, - span}) => { + WherePredicate::BoundPredicate(WhereBoundPredicate { + ref bound_generic_params, + ref bounded_ty, + ref bounds, + span, + }) => { self.with_in_scope_lifetime_defs( - &bound_generic_params.iter() - .filter_map(|p| match *p { - GenericParam::Lifetime(ref ld) => Some(ld.clone()), - _ => None, - }) - .collect::<Vec<_>>(), + bound_generic_params.iter().filter_map(|p| match p { + GenericParam::Lifetime(ld) => Some(ld), + _ => None, + }), |this| { hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate { - bound_generic_params: - this.lower_generic_params(bound_generic_params, &NodeMap()), + bound_generic_params: this.lower_generic_params( + bound_generic_params, + &NodeMap(), + ), bounded_ty: this.lower_ty(bounded_ty, ImplTraitContext::Disallowed), - bounds: bounds.iter().filter_map(|bound| match *bound { - // Ignore `?Trait` bounds. - // Tthey were copied into type parameters already. - TraitTyParamBound(_, TraitBoundModifier::Maybe) => None, - _ => Some(this.lower_ty_param_bound( - bound, ImplTraitContext::Disallowed)) - }).collect(), + bounds: bounds + .iter() + .filter_map(|bound| match *bound { + // Ignore `?Trait` bounds. + // Tthey were copied into type parameters already. + TraitTyParamBound(_, TraitBoundModifier::Maybe) => None, + _ => Some(this.lower_ty_param_bound( + bound, + ImplTraitContext::Disallowed, + )), + }) + .collect(), span, }) - } + }, ) } - WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime, - ref bounds, - span}) => { - hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate { - span, - lifetime: self.lower_lifetime(lifetime), - bounds: bounds.iter().map(|bound| self.lower_lifetime(bound)).collect(), - }) - } - WherePredicate::EqPredicate(WhereEqPredicate{ id, - ref lhs_ty, - ref rhs_ty, - span}) => { - hir::WherePredicate::EqPredicate(hir::WhereEqPredicate { - id: self.lower_node_id(id).node_id, - lhs_ty: self.lower_ty(lhs_ty, ImplTraitContext::Disallowed), - rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::Disallowed), - span, - }) - } + WherePredicate::RegionPredicate(WhereRegionPredicate { + ref lifetime, + ref bounds, + span, + }) => hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate { + span, + lifetime: self.lower_lifetime(lifetime), + bounds: bounds + .iter() + .map(|bound| self.lower_lifetime(bound)) + .collect(), + }), + WherePredicate::EqPredicate(WhereEqPredicate { + id, + ref lhs_ty, + ref rhs_ty, + span, + }) => hir::WherePredicate::EqPredicate(hir::WhereEqPredicate { + id: self.lower_node_id(id).node_id, + lhs_ty: self.lower_ty(lhs_ty, ImplTraitContext::Disallowed), + rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::Disallowed), + span, + }), } } fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData { match *vdata { - VariantData::Struct(ref fields, id) => { - hir::VariantData::Struct(fields.iter() - .enumerate() - .map(|f| self.lower_struct_field(f)) - .collect(), - self.lower_node_id(id).node_id) - } - VariantData::Tuple(ref fields, id) => { - hir::VariantData::Tuple(fields.iter() - .enumerate() - .map(|f| self.lower_struct_field(f)) - .collect(), - self.lower_node_id(id).node_id) - } + VariantData::Struct(ref fields, id) => hir::VariantData::Struct( + fields + .iter() + .enumerate() + .map(|f| self.lower_struct_field(f)) + .collect(), + self.lower_node_id(id).node_id, + ), + VariantData::Tuple(ref fields, id) => hir::VariantData::Tuple( + fields + .iter() + .enumerate() + .map(|f| self.lower_struct_field(f)) + .collect(), + self.lower_node_id(id).node_id, + ), VariantData::Unit(id) => hir::VariantData::Unit(self.lower_node_id(id).node_id), } } @@ -1794,7 +2072,7 @@ impl<'a> LoweringContext<'a> { fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext) -> hir::TraitRef { let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) { hir::QPath::Resolved(None, path) => path.and_then(|path| path), - qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath) + qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath), }; hir::TraitRef { path, @@ -1802,13 +2080,15 @@ impl<'a> LoweringContext<'a> { } } - fn lower_poly_trait_ref(&mut self, - p: &PolyTraitRef, - itctx: ImplTraitContext) - -> hir::PolyTraitRef { + fn lower_poly_trait_ref( + &mut self, + p: &PolyTraitRef, + itctx: ImplTraitContext, + ) -> hir::PolyTraitRef { let bound_generic_params = self.lower_generic_params(&p.bound_generic_params, &NodeMap()); let trait_ref = self.with_parent_impl_lifetime_defs( - &bound_generic_params.iter() + &bound_generic_params + .iter() .filter_map(|p| match *p { hir::GenericParam::Lifetime(ref ld) => Some(ld.clone()), _ => None, @@ -1831,7 +2111,10 @@ impl<'a> LoweringContext<'a> { name: self.lower_ident(match f.ident { Some(ident) => ident, // FIXME(jseyfried) positional field hygiene - None => Ident { name: Symbol::intern(&index.to_string()), ctxt: f.span.ctxt() }, + None => Ident { + name: Symbol::intern(&index.to_string()), + ctxt: f.span.ctxt(), + }, }), vis: self.lower_visibility(&f.vis, None), ty: self.lower_ty(&f.ty, ImplTraitContext::Disallowed), @@ -1855,9 +2138,15 @@ impl<'a> LoweringContext<'a> { } } - fn lower_bounds(&mut self, bounds: &[TyParamBound], itctx: ImplTraitContext) - -> hir::TyParamBounds { - bounds.iter().map(|bound| self.lower_ty_param_bound(bound, itctx)).collect() + fn lower_bounds( + &mut self, + bounds: &[TyParamBound], + itctx: ImplTraitContext, + ) -> hir::TyParamBounds { + bounds + .iter() + .map(|bound| self.lower_ty_param_bound(bound, itctx)) + .collect() } fn lower_block(&mut self, b: &Block, targeted_by_break: bool) -> P<hir::Block> { @@ -1891,13 +2180,14 @@ impl<'a> LoweringContext<'a> { }) } - fn lower_item_kind(&mut self, - id: NodeId, - name: &mut Name, - attrs: &hir::HirVec<Attribute>, - vis: &mut hir::Visibility, - i: &ItemKind) - -> hir::Item_ { + fn lower_item_kind( + &mut self, + id: NodeId, + name: &mut Name, + attrs: &hir::HirVec<Attribute>, + vis: &mut hir::Visibility, + i: &ItemKind, + ) -> hir::Item_ { match *i { ItemKind::ExternCrate(orig_name) => hir::ItemExternCrate(orig_name), ItemKind::Use(ref use_tree) => { @@ -1911,49 +2201,57 @@ impl<'a> LoweringContext<'a> { } ItemKind::Static(ref t, m, ref e) => { let value = self.lower_body(None, |this| this.lower_expr(e)); - hir::ItemStatic(self.lower_ty(t, ImplTraitContext::Disallowed), - self.lower_mutability(m), - value) + hir::ItemStatic( + self.lower_ty(t, ImplTraitContext::Disallowed), + self.lower_mutability(m), + value, + ) } ItemKind::Const(ref t, ref e) => { let value = self.lower_body(None, |this| this.lower_expr(e)); hir::ItemConst(self.lower_ty(t, ImplTraitContext::Disallowed), value) } ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => { - let fn_def_id = self.resolver.definitions().opt_local_def_id(id); + let fn_def_id = self.resolver.definitions().local_def_id(id); self.with_new_scopes(|this| { let body_id = this.lower_body(Some(decl), |this| { let body = this.lower_block(body, false); this.expr_block(body, ThinVec::new()) }); - let (generics, fn_decl) = - this.add_in_band_defs(generics, fn_def_id, |this| - this.lower_fn_decl(decl, fn_def_id, true)); - - hir::ItemFn(fn_decl, - this.lower_unsafety(unsafety), - this.lower_constness(constness), - abi, - generics, - body_id) + let (generics, fn_decl) = this.add_in_band_defs( + generics, + fn_def_id, + AnonymousLifetimeMode::PassThrough, + |this| this.lower_fn_decl(decl, Some(fn_def_id), true), + ); + + hir::ItemFn( + fn_decl, + this.lower_unsafety(unsafety), + this.lower_constness(constness), + abi, + generics, + body_id, + ) }) } ItemKind::Mod(ref m) => hir::ItemMod(self.lower_mod(m)), ItemKind::ForeignMod(ref nm) => hir::ItemForeignMod(self.lower_foreign_mod(nm)), ItemKind::GlobalAsm(ref ga) => hir::ItemGlobalAsm(self.lower_global_asm(ga)), - ItemKind::Ty(ref t, ref generics) => { - hir::ItemTy(self.lower_ty(t, ImplTraitContext::Disallowed), - self.lower_generics(generics)) - } - ItemKind::Enum(ref enum_definition, ref generics) => { - hir::ItemEnum(hir::EnumDef { - variants: enum_definition.variants - .iter() - .map(|x| self.lower_variant(x)) - .collect(), - }, - self.lower_generics(generics)) - } + ItemKind::Ty(ref t, ref generics) => hir::ItemTy( + self.lower_ty(t, ImplTraitContext::Disallowed), + self.lower_generics(generics), + ), + ItemKind::Enum(ref enum_definition, ref generics) => hir::ItemEnum( + hir::EnumDef { + variants: enum_definition + .variants + .iter() + .map(|x| self.lower_variant(x)) + .collect(), + }, + self.lower_generics(generics), + ), ItemKind::Struct(ref struct_def, ref generics) => { let struct_def = self.lower_variant_data(struct_def); hir::ItemStruct(struct_def, self.lower_generics(generics)) @@ -1962,21 +2260,40 @@ impl<'a> LoweringContext<'a> { let vdata = self.lower_variant_data(vdata); hir::ItemUnion(vdata, self.lower_generics(generics)) } - ItemKind::Impl(unsafety, - polarity, - defaultness, - ref ast_generics, - ref ifce, - ref ty, - ref impl_items) => { - let def_id = self.resolver.definitions().opt_local_def_id(id); - let (generics, (ifce, lowered_ty)) = - self.add_in_band_defs(ast_generics, def_id, |this| { - let ifce = ifce.as_ref().map(|trait_ref| { + ItemKind::Impl( + unsafety, + polarity, + defaultness, + ref ast_generics, + ref trait_ref, + ref ty, + ref impl_items, + ) => { + let def_id = self.resolver.definitions().local_def_id(id); + + // Lower the "impl header" first. This ordering is important + // for in-band lifetimes! Consider `'a` here: + // + // impl Foo<'a> for u32 { + // fn method(&'a self) { .. } + // } + // + // Because we start by lowering the `Foo<'a> for u32` + // part, we will add `'a` to the list of generics on + // the impl. When we then encounter it later in the + // method, it will not be considered an in-band + // lifetime to be added, but rather a reference to a + // parent lifetime. + let (generics, (trait_ref, lowered_ty)) = self.add_in_band_defs( + ast_generics, + def_id, + AnonymousLifetimeMode::CreateParameter, + |this| { + let trait_ref = trait_ref.as_ref().map(|trait_ref| { this.lower_trait_ref(trait_ref, ImplTraitContext::Disallowed) }); - if let Some(ref trait_ref) = ifce { + if let Some(ref trait_ref) = trait_ref { if let Def::Trait(def_id) = trait_ref.path.def { this.trait_impls.entry(def_id).or_insert(vec![]).push(id); } @@ -1984,46 +2301,51 @@ impl<'a> LoweringContext<'a> { let lowered_ty = this.lower_ty(ty, ImplTraitContext::Disallowed); - (ifce, lowered_ty) - }); + (trait_ref, lowered_ty) + }, + ); let new_impl_items = self.with_in_scope_lifetime_defs( - &ast_generics.params - .iter() - .filter_map(|p| match *p { - GenericParam::Lifetime(ref ld) => Some(ld.clone()), - _ => None, - }) - .collect::<Vec<_>>(), + ast_generics.params.iter().filter_map(|p| match p { + GenericParam::Lifetime(ld) => Some(ld), + _ => None, + }), |this| { - impl_items.iter() + impl_items + .iter() .map(|item| this.lower_impl_item_ref(item)) .collect() - } + }, ); - - hir::ItemImpl(self.lower_unsafety(unsafety), - self.lower_impl_polarity(polarity), - self.lower_defaultness(defaultness, true /* [1] */), - generics, - ifce, - lowered_ty, - new_impl_items) + hir::ItemImpl( + self.lower_unsafety(unsafety), + self.lower_impl_polarity(polarity), + self.lower_defaultness(defaultness, true /* [1] */), + generics, + trait_ref, + lowered_ty, + new_impl_items, + ) } ItemKind::Trait(is_auto, unsafety, ref generics, ref bounds, ref items) => { let bounds = self.lower_bounds(bounds, ImplTraitContext::Disallowed); - let items = items.iter().map(|item| self.lower_trait_item_ref(item)).collect(); - hir::ItemTrait(self.lower_is_auto(is_auto), - self.lower_unsafety(unsafety), - self.lower_generics(generics), - bounds, - items) - } - ItemKind::TraitAlias(ref generics, ref bounds) => { - hir::ItemTraitAlias(self.lower_generics(generics), - self.lower_bounds(bounds, ImplTraitContext::Disallowed)) + let items = items + .iter() + .map(|item| self.lower_trait_item_ref(item)) + .collect(); + hir::ItemTrait( + self.lower_is_auto(is_auto), + self.lower_unsafety(unsafety), + self.lower_generics(generics), + bounds, + items, + ) } + ItemKind::TraitAlias(ref generics, ref bounds) => hir::ItemTraitAlias( + self.lower_generics(generics), + self.lower_bounds(bounds, ImplTraitContext::Disallowed), + ), ItemKind::MacroDef(..) | ItemKind::Mac(..) => panic!("Shouldn't still be around"), } @@ -2031,14 +2353,15 @@ impl<'a> LoweringContext<'a> { // not cause an assertion failure inside the `lower_defaultness` function } - fn lower_use_tree(&mut self, - tree: &UseTree, - prefix: &Path, - id: NodeId, - vis: &mut hir::Visibility, - name: &mut Name, - attrs: &hir::HirVec<Attribute>) - -> hir::Item_ { + fn lower_use_tree( + &mut self, + tree: &UseTree, + prefix: &Path, + id: NodeId, + vis: &mut hir::Visibility, + name: &mut Name, + attrs: &hir::HirVec<Attribute>, + ) -> hir::Item_ { let path = &tree.prefix; match tree.kind { @@ -2047,17 +2370,19 @@ impl<'a> LoweringContext<'a> { // First apply the prefix to the path let mut path = Path { - segments: prefix.segments + segments: prefix + .segments .iter() .chain(path.segments.iter()) .cloned() .collect(), - span: path.span + span: path.span, }; // Correctly resolve `self` imports - if path.segments.len() > 1 && - path.segments.last().unwrap().identifier.name == keywords::SelfValue.name() { + if path.segments.len() > 1 + && path.segments.last().unwrap().identifier.name == keywords::SelfValue.name() + { let _ = path.segments.pop(); if rename.is_none() { *name = path.segments.last().unwrap().identifier.name; @@ -2068,19 +2393,25 @@ impl<'a> LoweringContext<'a> { hir::ItemUse(path, hir::UseKind::Single) } UseTreeKind::Glob => { - let path = P(self.lower_path(id, &Path { - segments: prefix.segments - .iter() - .chain(path.segments.iter()) - .cloned() - .collect(), - span: path.span, - }, ParamMode::Explicit)); + let path = P(self.lower_path( + id, + &Path { + segments: prefix + .segments + .iter() + .chain(path.segments.iter()) + .cloned() + .collect(), + span: path.span, + }, + ParamMode::Explicit, + )); hir::ItemUse(path, hir::UseKind::Glob) } UseTreeKind::Nested(ref trees) => { let prefix = Path { - segments: prefix.segments + segments: prefix + .segments .iter() .chain(path.segments.iter()) .cloned() @@ -2098,16 +2429,15 @@ impl<'a> LoweringContext<'a> { let mut vis = vis.clone(); let mut name = name.clone(); - let item = self.lower_use_tree( - use_tree, &prefix, new_id, &mut vis, &mut name, &attrs, - ); + let item = + self.lower_use_tree(use_tree, &prefix, new_id, &mut vis, &mut name, &attrs); self.with_hir_id_owner(new_id, |this| { let vis = match vis { hir::Visibility::Public => hir::Visibility::Public, hir::Visibility::Crate => hir::Visibility::Crate, hir::Visibility::Inherited => hir::Visibility::Inherited, - hir::Visibility::Restricted { ref path, id: _ } => { + hir::Visibility::Restricted { ref path, id: _ } => { hir::Visibility::Restricted { path: path.clone(), // We are allocating a new NodeId here @@ -2116,15 +2446,18 @@ impl<'a> LoweringContext<'a> { } }; - this.items.insert(new_id, hir::Item { - id: new_id, - hir_id: new_hir_id, - name: name, - attrs: attrs.clone(), - node: item, - vis, - span: use_tree.span, - }); + this.items.insert( + new_id, + hir::Item { + id: new_id, + hir_id: new_hir_id, + name: name, + attrs: attrs.clone(), + node: item, + vis, + span: use_tree.span, + }, + ); }); } @@ -2141,25 +2474,31 @@ impl<'a> LoweringContext<'a> { fn lower_trait_item(&mut self, i: &TraitItem) -> hir::TraitItem { self.with_parent_def(i.id, |this| { let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id); - let fn_def_id = this.resolver.definitions().opt_local_def_id(node_id); + let trait_item_def_id = this.resolver.definitions().local_def_id(node_id); let (generics, node) = match i.node { - TraitItemKind::Const(ref ty, ref default) => { - ( - this.lower_generics(&i.generics), - hir::TraitItemKind::Const( - this.lower_ty(ty, ImplTraitContext::Disallowed), - default.as_ref().map(|x| { - this.lower_body(None, |this| this.lower_expr(x)) - })) - ) - } + TraitItemKind::Const(ref ty, ref default) => ( + this.lower_generics(&i.generics), + hir::TraitItemKind::Const( + this.lower_ty(ty, ImplTraitContext::Disallowed), + default + .as_ref() + .map(|x| this.lower_body(None, |this| this.lower_expr(x))), + ), + ), TraitItemKind::Method(ref sig, None) => { let names = this.lower_fn_args_to_names(&sig.decl); - this.add_in_band_defs(&i.generics, fn_def_id, |this| - hir::TraitItemKind::Method( - this.lower_method_sig(sig, fn_def_id, false), - hir::TraitMethod::Required(names))) + this.add_in_band_defs( + &i.generics, + trait_item_def_id, + AnonymousLifetimeMode::PassThrough, + |this| { + hir::TraitItemKind::Method( + this.lower_method_sig(sig, trait_item_def_id, false), + hir::TraitMethod::Required(names), + ) + }, + ) } TraitItemKind::Method(ref sig, Some(ref body)) => { let body_id = this.lower_body(Some(&sig.decl), |this| { @@ -2167,21 +2506,27 @@ impl<'a> LoweringContext<'a> { this.expr_block(body, ThinVec::new()) }); - this.add_in_band_defs(&i.generics, fn_def_id, |this| - hir::TraitItemKind::Method( - this.lower_method_sig(sig, fn_def_id, false), - hir::TraitMethod::Provided(body_id))) - } - TraitItemKind::Type(ref bounds, ref default) => { - ( - this.lower_generics(&i.generics), - hir::TraitItemKind::Type( - this.lower_bounds(bounds, ImplTraitContext::Disallowed), - default.as_ref().map(|x| { - this.lower_ty(x, ImplTraitContext::Disallowed) - })) + this.add_in_band_defs( + &i.generics, + trait_item_def_id, + AnonymousLifetimeMode::PassThrough, + |this| { + hir::TraitItemKind::Method( + this.lower_method_sig(sig, trait_item_def_id, false), + hir::TraitMethod::Provided(body_id), + ) + }, ) } + TraitItemKind::Type(ref bounds, ref default) => ( + this.lower_generics(&i.generics), + hir::TraitItemKind::Type( + this.lower_bounds(bounds, ImplTraitContext::Disallowed), + default + .as_ref() + .map(|x| this.lower_ty(x, ImplTraitContext::Disallowed)), + ), + ), TraitItemKind::Macro(..) => panic!("Shouldn't exist any more"), }; @@ -2205,11 +2550,12 @@ impl<'a> LoweringContext<'a> { TraitItemKind::Type(_, ref default) => { (hir::AssociatedItemKind::Type, default.is_some()) } - TraitItemKind::Method(ref sig, ref default) => { - (hir::AssociatedItemKind::Method { + TraitItemKind::Method(ref sig, ref default) => ( + hir::AssociatedItemKind::Method { has_self: sig.decl.has_self(), - }, default.is_some()) - } + }, + default.is_some(), + ), TraitItemKind::Macro(..) => unimplemented!(), }; hir::TraitItemRef { @@ -2224,7 +2570,7 @@ impl<'a> LoweringContext<'a> { fn lower_impl_item(&mut self, i: &ImplItem) -> hir::ImplItem { self.with_parent_def(i.id, |this| { let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id); - let fn_def_id = this.resolver.definitions().opt_local_def_id(node_id); + let impl_item_def_id = this.resolver.definitions().local_def_id(node_id); let (generics, node) = match i.node { ImplItemKind::Const(ref ty, ref expr) => { @@ -2233,8 +2579,8 @@ impl<'a> LoweringContext<'a> { this.lower_generics(&i.generics), hir::ImplItemKind::Const( this.lower_ty(ty, ImplTraitContext::Disallowed), - body_id - ) + body_id, + ), ) } ImplItemKind::Method(ref sig, ref body) => { @@ -2244,15 +2590,25 @@ impl<'a> LoweringContext<'a> { }); let impl_trait_return_allow = !this.is_in_trait_impl; - this.add_in_band_defs(&i.generics, fn_def_id, |this| - hir::ImplItemKind::Method( - this.lower_method_sig(sig, fn_def_id, impl_trait_return_allow), - body_id)) + this.add_in_band_defs( + &i.generics, + impl_item_def_id, + AnonymousLifetimeMode::PassThrough, + |this| { + hir::ImplItemKind::Method( + this.lower_method_sig( + sig, + impl_item_def_id, + impl_trait_return_allow, + ), + body_id, + ) + }, + ) } ImplItemKind::Type(ref ty) => ( this.lower_generics(&i.generics), - hir::ImplItemKind::Type( - this.lower_ty(ty, ImplTraitContext::Disallowed)), + hir::ImplItemKind::Type(this.lower_ty(ty, ImplTraitContext::Disallowed)), ), ImplItemKind::Macro(..) => panic!("Shouldn't exist any more"), }; @@ -2283,10 +2639,8 @@ impl<'a> LoweringContext<'a> { kind: match i.node { ImplItemKind::Const(..) => hir::AssociatedItemKind::Const, ImplItemKind::Type(..) => hir::AssociatedItemKind::Type, - ImplItemKind::Method(ref sig, _) => { - hir::AssociatedItemKind::Method { - has_self: sig.decl.has_self(), - } + ImplItemKind::Method(ref sig, _) => hir::AssociatedItemKind::Method { + has_self: sig.decl.has_self(), }, ImplItemKind::Macro(..) => unimplemented!(), }, @@ -2317,12 +2671,10 @@ impl<'a> LoweringContext<'a> { fn lower_item_id_use_tree(&self, tree: &UseTree, vec: &mut SmallVector<hir::ItemId>) { match tree.kind { - UseTreeKind::Nested(ref nested_vec) => { - for &(ref nested, id) in nested_vec { - vec.push(hir::ItemId { id, }); - self.lower_item_id_use_tree(nested, vec); - } - } + UseTreeKind::Nested(ref nested_vec) => for &(ref nested, id) in nested_vec { + vec.push(hir::ItemId { id }); + self.lower_item_id_use_tree(nested, vec); + }, UseTreeKind::Glob => {} UseTreeKind::Simple(..) => {} } @@ -2375,25 +2727,25 @@ impl<'a> LoweringContext<'a> { attrs: this.lower_attrs(&i.attrs), node: match i.node { ForeignItemKind::Fn(ref fdec, ref generics) => { - // Disallow impl Trait in foreign items - let (generics, (fn_dec, fn_args)) = - this.add_in_band_defs( - generics, - Some(def_id), - |this| ( + let (generics, (fn_dec, fn_args)) = this.add_in_band_defs( + generics, + def_id, + AnonymousLifetimeMode::PassThrough, + |this| { + ( + // Disallow impl Trait in foreign items this.lower_fn_decl(fdec, None, false), - this.lower_fn_args_to_names(fdec) + this.lower_fn_args_to_names(fdec), ) - ); + }, + ); hir::ForeignItemFn(fn_dec, fn_args, generics) } ForeignItemKind::Static(ref t, m) => { hir::ForeignItemStatic(this.lower_ty(t, ImplTraitContext::Disallowed), m) } - ForeignItemKind::Ty => { - hir::ForeignItemType - } + ForeignItemKind::Ty => hir::ForeignItemType, }, vis: this.lower_visibility(&i.vis, None), span: i.span, @@ -2401,16 +2753,17 @@ impl<'a> LoweringContext<'a> { }) } - fn lower_method_sig(&mut self, - sig: &MethodSig, - fn_def_id: Option<DefId>, - impl_trait_return_allow: bool) - -> hir::MethodSig { + fn lower_method_sig( + &mut self, + sig: &MethodSig, + fn_def_id: DefId, + impl_trait_return_allow: bool, + ) -> hir::MethodSig { hir::MethodSig { abi: sig.abi, unsafety: self.lower_unsafety(sig.unsafety), constness: self.lower_constness(sig.constness), - decl: self.lower_fn_decl(&sig.decl, fn_def_id, impl_trait_return_allow), + decl: self.lower_fn_decl(&sig.decl, Some(fn_def_id), impl_trait_return_allow), } } @@ -2478,52 +2831,67 @@ impl<'a> LoweringContext<'a> { def @ None | def @ Some(Def::Local(_)) => { let canonical_id = match def { Some(Def::Local(id)) => id, - _ => p.id + _ => p.id, }; - hir::PatKind::Binding(self.lower_binding_mode(binding_mode), - canonical_id, - respan(pth1.span, pth1.node.name), - sub.as_ref().map(|x| self.lower_pat(x))) + hir::PatKind::Binding( + self.lower_binding_mode(binding_mode), + canonical_id, + respan(pth1.span, pth1.node.name), + sub.as_ref().map(|x| self.lower_pat(x)), + ) } - Some(def) => { - hir::PatKind::Path(hir::QPath::Resolved(None, P(hir::Path { + Some(def) => hir::PatKind::Path(hir::QPath::Resolved( + None, + P(hir::Path { span: pth1.span, def, - segments: hir_vec![ - hir::PathSegment::from_name(pth1.node.name) - ], - }))) - } + segments: hir_vec![hir::PathSegment::from_name(pth1.node.name)], + }), + )), } } PatKind::Lit(ref e) => hir::PatKind::Lit(P(self.lower_expr(e))), PatKind::TupleStruct(ref path, ref pats, ddpos) => { - let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional, - ImplTraitContext::Disallowed); - hir::PatKind::TupleStruct(qpath, - pats.iter().map(|x| self.lower_pat(x)).collect(), - ddpos) - } - PatKind::Path(ref qself, ref path) => { - hir::PatKind::Path(self.lower_qpath(p.id, qself, path, ParamMode::Optional, - ImplTraitContext::Disallowed)) + let qpath = self.lower_qpath( + p.id, + &None, + path, + ParamMode::Optional, + ImplTraitContext::Disallowed, + ); + hir::PatKind::TupleStruct( + qpath, + pats.iter().map(|x| self.lower_pat(x)).collect(), + ddpos, + ) } + PatKind::Path(ref qself, ref path) => hir::PatKind::Path(self.lower_qpath( + p.id, + qself, + path, + ParamMode::Optional, + ImplTraitContext::Disallowed, + )), PatKind::Struct(ref path, ref fields, etc) => { - let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional, - ImplTraitContext::Disallowed); - - let fs = fields.iter() - .map(|f| { - Spanned { - span: f.span, - node: hir::FieldPat { - name: self.lower_ident(f.node.ident), - pat: self.lower_pat(&f.node.pat), - is_shorthand: f.node.is_shorthand, - }, - } - }) - .collect(); + let qpath = self.lower_qpath( + p.id, + &None, + path, + ParamMode::Optional, + ImplTraitContext::Disallowed, + ); + + let fs = fields + .iter() + .map(|f| Spanned { + span: f.span, + node: hir::FieldPat { + name: self.lower_ident(f.node.ident), + pat: self.lower_pat(&f.node.pat), + is_shorthand: f.node.is_shorthand, + }, + }) + .collect(); hir::PatKind::Struct(qpath, fs, etc) } PatKind::Tuple(ref elts, ddpos) => { @@ -2533,16 +2901,16 @@ impl<'a> LoweringContext<'a> { PatKind::Ref(ref inner, mutbl) => { hir::PatKind::Ref(self.lower_pat(inner), self.lower_mutability(mutbl)) } - PatKind::Range(ref e1, ref e2, ref end) => { - hir::PatKind::Range(P(self.lower_expr(e1)), - P(self.lower_expr(e2)), - self.lower_range_end(end)) - } - PatKind::Slice(ref before, ref slice, ref after) => { - hir::PatKind::Slice(before.iter().map(|x| self.lower_pat(x)).collect(), - slice.as_ref().map(|x| self.lower_pat(x)), - after.iter().map(|x| self.lower_pat(x)).collect()) - } + PatKind::Range(ref e1, ref e2, ref end) => hir::PatKind::Range( + P(self.lower_expr(e1)), + P(self.lower_expr(e2)), + self.lower_range_end(end), + ), + PatKind::Slice(ref before, ref slice, ref after) => hir::PatKind::Slice( + before.iter().map(|x| self.lower_pat(x)).collect(), + slice.as_ref().map(|x| self.lower_pat(x)), + after.iter().map(|x| self.lower_pat(x)).collect(), + ), PatKind::Paren(ref inner) => return self.lower_pat(inner), PatKind::Mac(_) => panic!("Shouldn't exist here"), }; @@ -2581,9 +2949,7 @@ impl<'a> LoweringContext<'a> { // } // // But for now there are type-inference issues doing that. - ExprKind::Box(ref inner) => { - hir::ExprBox(P(self.lower_expr(inner))) - } + ExprKind::Box(ref inner) => hir::ExprBox(P(self.lower_expr(inner))), // Desugar ExprBox: `in (PLACE) EXPR` ExprKind::InPlace(ref placer, ref value_expr) => { @@ -2624,9 +2990,7 @@ impl<'a> LoweringContext<'a> { }; // let placer = <placer_expr> ; - let (s1, placer_binding) = { - mk_stmt_let(self, placer_ident, placer_expr) - }; + let (s1, placer_binding) = { mk_stmt_let(self, placer_ident, placer_expr) }; // let mut place = Placer::make_place(placer); let (s2, place_binding) = { @@ -2645,11 +3009,13 @@ impl<'a> LoweringContext<'a> { // pop_unsafe!(EXPR)); let pop_unsafe_expr = { - self.signal_block_expr(hir_vec![], - value_expr, - e.span, - hir::PopUnsafeBlock(hir::CompilerGenerated), - ThinVec::new()) + self.signal_block_expr( + hir_vec![], + value_expr, + e.span, + hir::PopUnsafeBlock(hir::CompilerGenerated), + ThinVec::new(), + ) }; // push_unsafe!({ @@ -2658,19 +3024,21 @@ impl<'a> LoweringContext<'a> { // }) let expr = { let ptr = self.expr_ident(e.span, p_ptr_ident, p_ptr_binding); - let call_move_val_init = - hir::StmtSemi( - make_call(self, &move_val_init, hir_vec![ptr, pop_unsafe_expr]), - self.next_id().node_id); + let call_move_val_init = hir::StmtSemi( + make_call(self, &move_val_init, hir_vec![ptr, pop_unsafe_expr]), + self.next_id().node_id, + ); let call_move_val_init = respan(e.span, call_move_val_init); let place = self.expr_ident(e.span, place_ident, place_binding); let call = make_call(self, &inplace_finalize, hir_vec![place]); - P(self.signal_block_expr(hir_vec![call_move_val_init], - call, - e.span, - hir::PushUnsafeBlock(hir::CompilerGenerated), - ThinVec::new())) + P(self.signal_block_expr( + hir_vec![call_move_val_init], + call, + e.span, + hir::PushUnsafeBlock(hir::CompilerGenerated), + ThinVec::new(), + )) }; let block = self.block_all(e.span, hir_vec![s1, s2, s3], Some(expr)); @@ -2693,9 +3061,14 @@ impl<'a> LoweringContext<'a> { hir::ExprCall(f, args.iter().map(|x| self.lower_expr(x)).collect()) } ExprKind::MethodCall(ref seg, ref args) => { - let hir_seg = self.lower_path_segment(e.span, seg, ParamMode::Optional, 0, - ParenthesizedGenericArgs::Err, - ImplTraitContext::Disallowed); + let hir_seg = self.lower_path_segment( + e.span, + seg, + ParamMode::Optional, + 0, + ParenthesizedGenericArgs::Err, + ImplTraitContext::Disallowed, + ); let args = args.iter().map(|x| self.lower_expr(x)).collect(); hir::ExprMethodCall(hir_seg, seg.span, args) } @@ -2733,10 +3106,7 @@ impl<'a> LoweringContext<'a> { // wrap the if-let expr in a block let span = els.span; let els = P(self.lower_expr(els)); - let LoweredNodeId { - node_id, - hir_id, - } = self.next_id(); + let LoweredNodeId { node_id, hir_id } = self.next_id(); let blk = P(hir::Block { stmts: hir_vec![], expr: Some(els), @@ -2758,28 +3128,28 @@ impl<'a> LoweringContext<'a> { hir::ExprIf(P(self.lower_expr(cond)), P(then_expr), else_opt) } - ExprKind::While(ref cond, ref body, opt_label) => { - self.with_loop_scope(e.id, |this| - hir::ExprWhile( - this.with_loop_condition_scope(|this| P(this.lower_expr(cond))), - this.lower_block(body, false), - this.lower_label(opt_label))) - } - ExprKind::Loop(ref body, opt_label) => { - self.with_loop_scope(e.id, |this| - hir::ExprLoop(this.lower_block(body, false), - this.lower_label(opt_label), - hir::LoopSource::Loop)) - } + ExprKind::While(ref cond, ref body, opt_label) => self.with_loop_scope(e.id, |this| { + hir::ExprWhile( + this.with_loop_condition_scope(|this| P(this.lower_expr(cond))), + this.lower_block(body, false), + this.lower_label(opt_label), + ) + }), + ExprKind::Loop(ref body, opt_label) => self.with_loop_scope(e.id, |this| { + hir::ExprLoop( + this.lower_block(body, false), + this.lower_label(opt_label), + hir::LoopSource::Loop, + ) + }), ExprKind::Catch(ref body) => { - self.with_catch_scope(body.id, |this| - hir::ExprBlock(this.lower_block(body, true))) - } - ExprKind::Match(ref expr, ref arms) => { - hir::ExprMatch(P(self.lower_expr(expr)), - arms.iter().map(|x| self.lower_arm(x)).collect(), - hir::MatchSource::Normal) + self.with_catch_scope(body.id, |this| hir::ExprBlock(this.lower_block(body, true))) } + ExprKind::Match(ref expr, ref arms) => hir::ExprMatch( + P(self.lower_expr(expr)), + arms.iter().map(|x| self.lower_arm(x)).collect(), + hir::MatchSource::Normal, + ), ExprKind::Closure(capture_clause, movability, ref decl, ref body, fn_decl_span) => { self.with_new_scopes(|this| { this.with_parent_def(e.id, |this| { @@ -2791,8 +3161,12 @@ impl<'a> LoweringContext<'a> { }); let generator_option = if is_generator { if !decl.inputs.is_empty() { - span_err!(this.sess, fn_decl_span, E0628, - "generators cannot have explicit arguments"); + span_err!( + this.sess, + fn_decl_span, + E0628, + "generators cannot have explicit arguments" + ); this.sess.abort_if_errors(); } Some(match movability { @@ -2801,16 +3175,22 @@ impl<'a> LoweringContext<'a> { }) } else { if movability == Movability::Static { - span_err!(this.sess, fn_decl_span, E0906, - "closures cannot be static"); + span_err!( + this.sess, + fn_decl_span, + E0906, + "closures cannot be static" + ); } None }; - hir::ExprClosure(this.lower_capture_clause(capture_clause), - this.lower_fn_decl(decl, None, false), - body_id, - fn_decl_span, - generator_option) + hir::ExprClosure( + this.lower_capture_clause(capture_clause), + this.lower_fn_decl(decl, None, false), + body_id, + fn_decl_span, + generator_option, + ) }) }) } @@ -2818,18 +3198,16 @@ impl<'a> LoweringContext<'a> { ExprKind::Assign(ref el, ref er) => { hir::ExprAssign(P(self.lower_expr(el)), P(self.lower_expr(er))) } - ExprKind::AssignOp(op, ref el, ref er) => { - hir::ExprAssignOp(self.lower_binop(op), - P(self.lower_expr(el)), - P(self.lower_expr(er))) - } - ExprKind::Field(ref el, ident) => { - hir::ExprField(P(self.lower_expr(el)), - respan(ident.span, self.lower_ident(ident.node))) - } - ExprKind::TupField(ref el, ident) => { - hir::ExprTupField(P(self.lower_expr(el)), ident) - } + ExprKind::AssignOp(op, ref el, ref er) => hir::ExprAssignOp( + self.lower_binop(op), + P(self.lower_expr(el)), + P(self.lower_expr(er)), + ), + ExprKind::Field(ref el, ident) => hir::ExprField( + P(self.lower_expr(el)), + respan(ident.span, self.lower_ident(ident.node)), + ), + ExprKind::TupField(ref el, ident) => hir::ExprTupField(P(self.lower_expr(el)), ident), ExprKind::Index(ref el, ref er) => { hir::ExprIndex(P(self.lower_expr(el)), P(self.lower_expr(er))) } @@ -2843,25 +3221,27 @@ impl<'a> LoweringContext<'a> { (&Some(..), &Some(..), HalfOpen) => "Range", (&None, &Some(..), Closed) => "RangeToInclusive", (&Some(..), &Some(..), Closed) => "RangeInclusive", - (_, &None, Closed) => - self.diagnostic().span_fatal( - e.span, "inclusive range with no end").raise(), + (_, &None, Closed) => self.diagnostic() + .span_fatal(e.span, "inclusive range with no end") + .raise(), }; - let fields = - e1.iter().map(|e| ("start", e)).chain(e2.iter().map(|e| ("end", e))) + let fields = e1.iter() + .map(|e| ("start", e)) + .chain(e2.iter().map(|e| ("end", e))) .map(|(s, e)| { let expr = P(self.lower_expr(&e)); let unstable_span = self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span); self.field(Symbol::intern(s), expr, unstable_span) - }).collect::<P<[hir::Field]>>(); + }) + .collect::<P<[hir::Field]>>(); let is_unit = fields.is_empty(); let unstable_span = self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span); - let struct_path = - iter::once("ops").chain(iter::once(path)) + let struct_path = iter::once("ops") + .chain(iter::once(path)) .collect::<Vec<_>>(); let struct_path = self.std_path(unstable_span, &struct_path, is_unit); let struct_path = hir::QPath::Resolved(None, P(struct_path)); @@ -2880,46 +3260,53 @@ impl<'a> LoweringContext<'a> { attrs: e.attrs.clone(), }; } - ExprKind::Path(ref qself, ref path) => { - hir::ExprPath(self.lower_qpath(e.id, qself, path, ParamMode::Optional, - ImplTraitContext::Disallowed)) - } + ExprKind::Path(ref qself, ref path) => hir::ExprPath(self.lower_qpath( + e.id, + qself, + path, + ParamMode::Optional, + ImplTraitContext::Disallowed, + )), ExprKind::Break(opt_label, ref opt_expr) => { let destination = if self.is_in_loop_condition && opt_label.is_none() { hir::Destination { label: None, target_id: hir::ScopeTarget::Loop( - Err(hir::LoopIdError::UnlabeledCfInWhileCondition).into()), + Err(hir::LoopIdError::UnlabeledCfInWhileCondition).into(), + ), } } else { self.lower_loop_destination(opt_label.map(|label| (e.id, label))) }; hir::ExprBreak( - destination, - opt_expr.as_ref().map(|x| P(self.lower_expr(x)))) - } - ExprKind::Continue(opt_label) => - hir::ExprAgain( - if self.is_in_loop_condition && opt_label.is_none() { - hir::Destination { - label: None, - target_id: hir::ScopeTarget::Loop(Err( - hir::LoopIdError::UnlabeledCfInWhileCondition).into()), - } - } else { - self.lower_loop_destination(opt_label.map(|label| (e.id, label))) - }), + destination, + opt_expr.as_ref().map(|x| P(self.lower_expr(x))), + ) + } + ExprKind::Continue(opt_label) => { + hir::ExprAgain(if self.is_in_loop_condition && opt_label.is_none() { + hir::Destination { + label: None, + target_id: hir::ScopeTarget::Loop( + Err(hir::LoopIdError::UnlabeledCfInWhileCondition).into(), + ), + } + } else { + self.lower_loop_destination(opt_label.map(|label| (e.id, label))) + }) + } ExprKind::Ret(ref e) => hir::ExprRet(e.as_ref().map(|x| P(self.lower_expr(x)))), ExprKind::InlineAsm(ref asm) => { let hir_asm = hir::InlineAsm { inputs: asm.inputs.iter().map(|&(ref c, _)| c.clone()).collect(), - outputs: asm.outputs.iter().map(|out| { - hir::InlineAsmOutput { + outputs: asm.outputs + .iter() + .map(|out| hir::InlineAsmOutput { constraint: out.constraint.clone(), is_rw: out.is_rw, is_indirect: out.is_indirect, - } - }).collect(), + }) + .collect(), asm: asm.asm.clone(), asm_str_style: asm.asm_str_style, clobbers: asm.clobbers.clone().into(), @@ -2928,18 +3315,27 @@ impl<'a> LoweringContext<'a> { dialect: asm.dialect, ctxt: asm.ctxt, }; - let outputs = - asm.outputs.iter().map(|out| self.lower_expr(&out.expr)).collect(); - let inputs = - asm.inputs.iter().map(|&(_, ref input)| self.lower_expr(input)).collect(); + let outputs = asm.outputs + .iter() + .map(|out| self.lower_expr(&out.expr)) + .collect(); + let inputs = asm.inputs + .iter() + .map(|&(_, ref input)| self.lower_expr(input)) + .collect(); hir::ExprInlineAsm(P(hir_asm), outputs, inputs) } - ExprKind::Struct(ref path, ref fields, ref maybe_expr) => { - hir::ExprStruct(self.lower_qpath(e.id, &None, path, ParamMode::Optional, - ImplTraitContext::Disallowed), - fields.iter().map(|x| self.lower_field(x)).collect(), - maybe_expr.as_ref().map(|x| P(self.lower_expr(x)))) - } + ExprKind::Struct(ref path, ref fields, ref maybe_expr) => hir::ExprStruct( + self.lower_qpath( + e.id, + &None, + path, + ParamMode::Optional, + ImplTraitContext::Disallowed, + ), + fields.iter().map(|x| self.lower_field(x)).collect(), + maybe_expr.as_ref().map(|x| P(self.lower_expr(x))), + ), ExprKind::Paren(ref ex) => { let mut ex = self.lower_expr(ex); // include parens in span, but only if it is a super-span. @@ -2955,9 +3351,10 @@ impl<'a> LoweringContext<'a> { ExprKind::Yield(ref opt_expr) => { self.is_generator = true; - let expr = opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| { - self.expr(e.span, hir::ExprTup(hir_vec![]), ThinVec::new()) - }); + let expr = opt_expr + .as_ref() + .map(|x| self.lower_expr(x)) + .unwrap_or_else(|| self.expr(e.span, hir::ExprTup(hir_vec![]), ThinVec::new())); hir::ExprYield(P(expr)) } @@ -3002,7 +3399,8 @@ impl<'a> LoweringContext<'a> { arms.into(), hir::MatchSource::IfLetDesugar { contains_else_clause, - }) + }, + ) } // Desugar ExprWhileLet @@ -3019,11 +3417,13 @@ impl<'a> LoweringContext<'a> { // Note that the block AND the condition are evaluated in the loop scope. // This is done to allow `break` from inside the condition of the loop. - let (body, break_expr, sub_expr) = self.with_loop_scope(e.id, |this| ( - this.lower_block(body, false), - this.expr_break(e.span, ThinVec::new()), - this.with_loop_condition_scope(|this| P(this.lower_expr(sub_expr))), - )); + let (body, break_expr, sub_expr) = self.with_loop_scope(e.id, |this| { + ( + this.lower_block(body, false), + this.expr_break(e.span, ThinVec::new()), + this.with_loop_condition_scope(|this| P(this.lower_expr(sub_expr))), + ) + }); // `<pat> => <body>` let pat_arm = { @@ -3040,16 +3440,19 @@ impl<'a> LoweringContext<'a> { // `match <sub_expr> { ... }` let arms = hir_vec![pat_arm, break_arm]; - let match_expr = self.expr(sub_expr.span, - hir::ExprMatch(sub_expr, - arms, - hir::MatchSource::WhileLetDesugar), - ThinVec::new()); + let match_expr = self.expr( + sub_expr.span, + hir::ExprMatch(sub_expr, arms, hir::MatchSource::WhileLetDesugar), + ThinVec::new(), + ); // `[opt_ident]: loop { ... }` let loop_block = P(self.block_expr(P(match_expr))); - let loop_expr = hir::ExprLoop(loop_block, self.lower_label(opt_label), - hir::LoopSource::WhileLet); + let loop_expr = hir::ExprLoop( + loop_block, + self.lower_label(opt_label), + hir::LoopSource::WhileLet, + ); // add attributes to the outer returned expr node loop_expr } @@ -3083,9 +3486,11 @@ impl<'a> LoweringContext<'a> { let iter = self.str_to_ident("iter"); let next_ident = self.str_to_ident("__next"); - let next_pat = self.pat_ident_binding_mode(pat.span, - next_ident, - hir::BindingAnnotation::Mutable); + let next_pat = self.pat_ident_binding_mode( + pat.span, + next_ident, + hir::BindingAnnotation::Mutable, + ); // `::std::option::Option::Some(val) => next = val` let pat_arm = { @@ -3093,25 +3498,26 @@ impl<'a> LoweringContext<'a> { let val_pat = self.pat_ident(pat.span, val_ident); let val_expr = P(self.expr_ident(pat.span, val_ident, val_pat.id)); let next_expr = P(self.expr_ident(pat.span, next_ident, next_pat.id)); - let assign = P(self.expr(pat.span, - hir::ExprAssign(next_expr, val_expr), - ThinVec::new())); + let assign = P(self.expr( + pat.span, + hir::ExprAssign(next_expr, val_expr), + ThinVec::new(), + )); let some_pat = self.pat_some(pat.span, val_pat); self.arm(hir_vec![some_pat], assign) }; // `::std::option::Option::None => break` let break_arm = { - let break_expr = self.with_loop_scope(e.id, |this| - this.expr_break(e.span, ThinVec::new())); + let break_expr = + self.with_loop_scope(e.id, |this| this.expr_break(e.span, ThinVec::new())); let pat = self.pat_none(e.span); self.arm(hir_vec![pat], break_expr) }; // `mut iter` - let iter_pat = self.pat_ident_binding_mode(head_sp, - iter, - hir::BindingAnnotation::Mutable); + let iter_pat = + self.pat_ident_binding_mode(head_sp, iter, hir::BindingAnnotation::Mutable); // `match ::std::iter::Iterator::next(&mut iter) { ... }` let match_expr = { @@ -3119,46 +3525,48 @@ impl<'a> LoweringContext<'a> { let ref_mut_iter = self.expr_mut_addr_of(head_sp, iter); let next_path = &["iter", "Iterator", "next"]; let next_path = P(self.expr_std_path(head_sp, next_path, ThinVec::new())); - let next_expr = P(self.expr_call(head_sp, next_path, - hir_vec![ref_mut_iter])); + let next_expr = P(self.expr_call(head_sp, next_path, hir_vec![ref_mut_iter])); let arms = hir_vec![pat_arm, break_arm]; - P(self.expr(head_sp, - hir::ExprMatch(next_expr, arms, - hir::MatchSource::ForLoopDesugar), - ThinVec::new())) + P(self.expr( + head_sp, + hir::ExprMatch(next_expr, arms, hir::MatchSource::ForLoopDesugar), + ThinVec::new(), + )) }; let match_stmt = respan(head_sp, hir::StmtExpr(match_expr, self.next_id().node_id)); let next_expr = P(self.expr_ident(head_sp, next_ident, next_pat.id)); // `let mut __next` - let next_let = self.stmt_let_pat(head_sp, - None, - next_pat, - hir::LocalSource::ForLoopDesugar); + let next_let = + self.stmt_let_pat(head_sp, None, next_pat, hir::LocalSource::ForLoopDesugar); // `let <pat> = __next` let pat = self.lower_pat(pat); - let pat_let = self.stmt_let_pat(head_sp, + let pat_let = self.stmt_let_pat( + head_sp, Some(next_expr), pat, - hir::LocalSource::ForLoopDesugar); + hir::LocalSource::ForLoopDesugar, + ); let body_block = self.with_loop_scope(e.id, |this| this.lower_block(body, false)); let body_expr = P(self.expr_block(body_block, ThinVec::new())); let body_stmt = respan(body.span, hir::StmtExpr(body_expr, self.next_id().node_id)); - let loop_block = P(self.block_all(e.span, - hir_vec![next_let, - match_stmt, - pat_let, - body_stmt], - None)); + let loop_block = P(self.block_all( + e.span, + hir_vec![next_let, match_stmt, pat_let, body_stmt], + None, + )); // `[opt_ident]: loop { ... }` - let loop_expr = hir::ExprLoop(loop_block, self.lower_label(opt_label), - hir::LoopSource::ForLoop); + let loop_expr = hir::ExprLoop( + loop_block, + self.lower_label(opt_label), + hir::LoopSource::ForLoop, + ); let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id); let loop_expr = P(hir::Expr { id: node_id, @@ -3174,15 +3582,16 @@ impl<'a> LoweringContext<'a> { // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }` let into_iter_expr = { let into_iter_path = &["iter", "IntoIterator", "into_iter"]; - let into_iter = P(self.expr_std_path(head_sp, into_iter_path, - ThinVec::new())); + let into_iter = P(self.expr_std_path(head_sp, into_iter_path, ThinVec::new())); P(self.expr_call(head_sp, into_iter, hir_vec![head])) }; - let match_expr = P(self.expr_match(head_sp, - into_iter_expr, - hir_vec![iter_arm], - hir::MatchSource::ForLoopDesugar)); + let match_expr = P(self.expr_match( + head_sp, + into_iter_expr, + hir_vec![iter_arm], + hir::MatchSource::ForLoopDesugar, + )); // `{ let _result = ...; _result }` // underscore prevents an unused_variables lint if the head diverges @@ -3242,10 +3651,12 @@ impl<'a> LoweringContext<'a> { let ok_arm = { let val_ident = self.str_to_ident("val"); let val_pat = self.pat_ident(e.span, val_ident); - let val_expr = P(self.expr_ident_with_attrs(e.span, - val_ident, - val_pat.id, - ThinVec::from(attrs.clone()))); + let val_expr = P(self.expr_ident_with_attrs( + e.span, + val_ident, + val_pat.id, + ThinVec::from(attrs.clone()), + )); let ok_pat = self.pat_ok(e.span, val_pat); self.arm(hir_vec![ok_pat], val_expr) @@ -3265,8 +3676,7 @@ impl<'a> LoweringContext<'a> { }; let from_err_expr = { let path = &["ops", "Try", "from_error"]; - let from_err = P(self.expr_std_path(unstable_span, path, - ThinVec::new())); + let from_err = P(self.expr_std_path(unstable_span, path, ThinVec::new())); P(self.expr_call(e.span, from_err, hir_vec![from_expr])) }; @@ -3280,23 +3690,23 @@ impl<'a> LoweringContext<'a> { label: None, target_id: hir::ScopeTarget::Block(catch_node), }, - Some(from_err_expr) + Some(from_err_expr), ), - thin_attrs)) + thin_attrs, + )) } else { - P(self.expr(e.span, - hir::Expr_::ExprRet(Some(from_err_expr)), - thin_attrs)) + P(self.expr(e.span, hir::Expr_::ExprRet(Some(from_err_expr)), thin_attrs)) }; - let err_pat = self.pat_err(e.span, err_local); self.arm(hir_vec![err_pat], ret_expr) }; - hir::ExprMatch(discr, - hir_vec![err_arm, ok_arm], - hir::MatchSource::TryDesugar) + hir::ExprMatch( + discr, + hir_vec![err_arm, ok_arm], + hir::MatchSource::TryDesugar, + ) } ExprKind::Mac(_) => panic!("Shouldn't exist here"), @@ -3316,39 +3726,42 @@ impl<'a> LoweringContext<'a> { fn lower_stmt(&mut self, s: &Stmt) -> SmallVector<hir::Stmt> { SmallVector::one(match s.node { StmtKind::Local(ref l) => Spanned { - node: hir::StmtDecl(P(Spanned { - node: hir::DeclLocal(self.lower_local(l)), - span: s.span, - }), self.lower_node_id(s.id).node_id), + node: hir::StmtDecl( + P(Spanned { + node: hir::DeclLocal(self.lower_local(l)), + span: s.span, + }), + self.lower_node_id(s.id).node_id, + ), span: s.span, }, StmtKind::Item(ref it) => { // Can only use the ID once. let mut id = Some(s.id); - return self.lower_item_id(it).into_iter().map(|item_id| Spanned { - node: hir::StmtDecl(P(Spanned { - node: hir::DeclItem(item_id), + return self.lower_item_id(it) + .into_iter() + .map(|item_id| Spanned { + node: hir::StmtDecl( + P(Spanned { + node: hir::DeclItem(item_id), + span: s.span, + }), + id.take() + .map(|id| self.lower_node_id(id).node_id) + .unwrap_or_else(|| self.next_id().node_id), + ), span: s.span, - }), id.take() - .map(|id| self.lower_node_id(id).node_id) - .unwrap_or_else(|| self.next_id().node_id)), - span: s.span, - }).collect(); - } - StmtKind::Expr(ref e) => { - Spanned { - node: hir::StmtExpr(P(self.lower_expr(e)), - self.lower_node_id(s.id).node_id), - span: s.span, - } - } - StmtKind::Semi(ref e) => { - Spanned { - node: hir::StmtSemi(P(self.lower_expr(e)), - self.lower_node_id(s.id).node_id), - span: s.span, - } + }) + .collect(); } + StmtKind::Expr(ref e) => Spanned { + node: hir::StmtExpr(P(self.lower_expr(e)), self.lower_node_id(s.id).node_id), + span: s.span, + }, + StmtKind::Semi(ref e) => Spanned { + node: hir::StmtSemi(P(self.lower_expr(e)), self.lower_node_id(s.id).node_id), + span: s.span, + }, StmtKind::Mac(..) => panic!("Shouldn't exist here"), }) } @@ -3365,30 +3778,31 @@ impl<'a> LoweringContext<'a> { /// lowered. This can happen during `lower_impl_item_ref()` where we need to /// lower a `Visibility` value although we haven't lowered the owning /// `ImplItem` in question yet. - fn lower_visibility(&mut self, - v: &Visibility, - explicit_owner: Option<NodeId>) - -> hir::Visibility { + fn lower_visibility( + &mut self, + v: &Visibility, + explicit_owner: Option<NodeId>, + ) -> hir::Visibility { match v.node { VisibilityKind::Public => hir::Public, VisibilityKind::Crate(..) => hir::Visibility::Crate, - VisibilityKind::Restricted { ref path, id, .. } => { - hir::Visibility::Restricted { - path: P(self.lower_path(id, path, ParamMode::Explicit)), - id: if let Some(owner) = explicit_owner { - self.lower_node_id_with_owner(id, owner).node_id - } else { - self.lower_node_id(id).node_id - } - } - } + VisibilityKind::Restricted { ref path, id, .. } => hir::Visibility::Restricted { + path: P(self.lower_path(id, path, ParamMode::Explicit)), + id: if let Some(owner) = explicit_owner { + self.lower_node_id_with_owner(id, owner).node_id + } else { + self.lower_node_id(id).node_id + }, + }, VisibilityKind::Inherited => hir::Inherited, } } fn lower_defaultness(&mut self, d: Defaultness, has_value: bool) -> hir::Defaultness { match d { - Defaultness::Default => hir::Defaultness::Default { has_value: has_value }, + Defaultness::Default => hir::Defaultness::Default { + has_value: has_value, + }, Defaultness::Final => { assert!(has_value); hir::Defaultness::Final @@ -3405,8 +3819,7 @@ impl<'a> LoweringContext<'a> { fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation { match *b { - BindingMode::ByValue(Mutability::Immutable) => - hir::BindingAnnotation::Unannotated, + BindingMode::ByValue(Mutability::Immutable) => hir::BindingAnnotation::Unannotated, BindingMode::ByRef(Mutability::Immutable) => hir::BindingAnnotation::Ref, BindingMode::ByValue(Mutability::Mutable) => hir::BindingAnnotation::Mutable, BindingMode::ByRef(Mutability::Mutable) => hir::BindingAnnotation::RefMut, @@ -3447,10 +3860,7 @@ impl<'a> LoweringContext<'a> { fn field(&mut self, name: Name, expr: P<hir::Expr>, span: Span) -> hir::Field { hir::Field { - name: Spanned { - node: name, - span, - }, + name: Spanned { node: name, span }, span, expr, is_shorthand: false, @@ -3462,8 +3872,12 @@ impl<'a> LoweringContext<'a> { P(self.expr(span, expr_break, attrs)) } - fn expr_call(&mut self, span: Span, e: P<hir::Expr>, args: hir::HirVec<hir::Expr>) - -> hir::Expr { + fn expr_call( + &mut self, + span: Span, + e: P<hir::Expr>, + args: hir::HirVec<hir::Expr>, + ) -> hir::Expr { self.expr(span, hir::ExprCall(e, args), ThinVec::new()) } @@ -3471,15 +3885,21 @@ impl<'a> LoweringContext<'a> { self.expr_ident_with_attrs(span, id, binding, ThinVec::new()) } - fn expr_ident_with_attrs(&mut self, span: Span, - id: Name, - binding: NodeId, - attrs: ThinVec<Attribute>) -> hir::Expr { - let expr_path = hir::ExprPath(hir::QPath::Resolved(None, P(hir::Path { - span, - def: Def::Local(binding), - segments: hir_vec![hir::PathSegment::from_name(id)], - }))); + fn expr_ident_with_attrs( + &mut self, + span: Span, + id: Name, + binding: NodeId, + attrs: ThinVec<Attribute>, + ) -> hir::Expr { + let expr_path = hir::ExprPath(hir::QPath::Resolved( + None, + P(hir::Path { + span, + def: Def::Local(binding), + segments: hir_vec![hir::PathSegment::from_name(id)], + }), + )); self.expr(span, expr_path, attrs) } @@ -3488,21 +3908,27 @@ impl<'a> LoweringContext<'a> { self.expr(span, hir::ExprAddrOf(hir::MutMutable, e), ThinVec::new()) } - fn expr_std_path(&mut self, - span: Span, - components: &[&str], - attrs: ThinVec<Attribute>) - -> hir::Expr { + fn expr_std_path( + &mut self, + span: Span, + components: &[&str], + attrs: ThinVec<Attribute>, + ) -> hir::Expr { let path = self.std_path(span, components, true); - self.expr(span, hir::ExprPath(hir::QPath::Resolved(None, P(path))), attrs) + self.expr( + span, + hir::ExprPath(hir::QPath::Resolved(None, P(path))), + attrs, + ) } - fn expr_match(&mut self, - span: Span, - arg: P<hir::Expr>, - arms: hir::HirVec<hir::Arm>, - source: hir::MatchSource) - -> hir::Expr { + fn expr_match( + &mut self, + span: Span, + arg: P<hir::Expr>, + arms: hir::HirVec<hir::Arm>, + source: hir::MatchSource, + ) -> hir::Expr { self.expr(span, hir::ExprMatch(arg, arms, source), ThinVec::new()) } @@ -3525,12 +3951,13 @@ impl<'a> LoweringContext<'a> { } } - fn stmt_let_pat(&mut self, - sp: Span, - ex: Option<P<hir::Expr>>, - pat: P<hir::Pat>, - source: hir::LocalSource) - -> hir::Stmt { + fn stmt_let_pat( + &mut self, + sp: Span, + ex: Option<P<hir::Expr>>, + pat: P<hir::Pat>, + source: hir::LocalSource, + ) -> hir::Stmt { let LoweredNodeId { node_id, hir_id } = self.next_id(); let local = P(hir::Local { @@ -3547,23 +3974,35 @@ impl<'a> LoweringContext<'a> { respan(sp, hir::StmtDecl(P(decl), self.next_id().node_id)) } - fn stmt_let(&mut self, sp: Span, mutbl: bool, ident: Name, ex: P<hir::Expr>) - -> (hir::Stmt, NodeId) { + fn stmt_let( + &mut self, + sp: Span, + mutbl: bool, + ident: Name, + ex: P<hir::Expr>, + ) -> (hir::Stmt, NodeId) { let pat = if mutbl { self.pat_ident_binding_mode(sp, ident, hir::BindingAnnotation::Mutable) } else { self.pat_ident(sp, ident) }; let pat_id = pat.id; - (self.stmt_let_pat(sp, Some(ex), pat, hir::LocalSource::Normal), pat_id) + ( + self.stmt_let_pat(sp, Some(ex), pat, hir::LocalSource::Normal), + pat_id, + ) } fn block_expr(&mut self, expr: P<hir::Expr>) -> hir::Block { self.block_all(expr.span, hir::HirVec::new(), Some(expr)) } - fn block_all(&mut self, span: Span, stmts: hir::HirVec<hir::Stmt>, expr: Option<P<hir::Expr>>) - -> hir::Block { + fn block_all( + &mut self, + span: Span, + stmts: hir::HirVec<hir::Stmt>, + expr: Option<P<hir::Expr>>, + ) -> hir::Block { let LoweredNodeId { node_id, hir_id } = self.next_id(); hir::Block { @@ -3594,11 +4033,12 @@ impl<'a> LoweringContext<'a> { self.pat_std_enum(span, &["option", "Option", "None"], hir_vec![]) } - fn pat_std_enum(&mut self, - span: Span, - components: &[&str], - subpats: hir::HirVec<P<hir::Pat>>) - -> P<hir::Pat> { + fn pat_std_enum( + &mut self, + span: Span, + components: &[&str], + subpats: hir::HirVec<P<hir::Pat>>, + ) -> P<hir::Pat> { let path = self.std_path(span, components, true); let qpath = hir::QPath::Resolved(None, P(path)); let pt = if subpats.is_empty() { @@ -3613,20 +4053,18 @@ impl<'a> LoweringContext<'a> { self.pat_ident_binding_mode(span, name, hir::BindingAnnotation::Unannotated) } - fn pat_ident_binding_mode(&mut self, span: Span, name: Name, bm: hir::BindingAnnotation) - -> P<hir::Pat> { + fn pat_ident_binding_mode( + &mut self, + span: Span, + name: Name, + bm: hir::BindingAnnotation, + ) -> P<hir::Pat> { let LoweredNodeId { node_id, hir_id } = self.next_id(); P(hir::Pat { id: node_id, hir_id, - node: hir::PatKind::Binding(bm, - node_id, - Spanned { - span, - node: name, - }, - None), + node: hir::PatKind::Binding(bm, node_id, Spanned { span, node: name }, None), span, }) } @@ -3649,16 +4087,18 @@ impl<'a> LoweringContext<'a> { /// `fld.cx.use_std`, and `::core::b::c::d` otherwise. /// The path is also resolved according to `is_value`. fn std_path(&mut self, span: Span, components: &[&str], is_value: bool) -> hir::Path { - self.resolver.resolve_str_path(span, self.crate_root, components, is_value) + self.resolver + .resolve_str_path(span, self.crate_root, components, is_value) } - fn signal_block_expr(&mut self, - stmts: hir::HirVec<hir::Stmt>, - expr: P<hir::Expr>, - span: Span, - rule: hir::BlockCheckMode, - attrs: ThinVec<Attribute>) - -> hir::Expr { + fn signal_block_expr( + &mut self, + stmts: hir::HirVec<hir::Stmt>, + expr: P<hir::Expr>, + span: Span, + rule: hir::BlockCheckMode, + attrs: ThinVec<Attribute>, + ) -> hir::Expr { let LoweredNodeId { node_id, hir_id } = self.next_id(); let block = P(hir::Block { @@ -3692,17 +4132,93 @@ impl<'a> LoweringContext<'a> { // The original ID is taken by the `PolyTraitRef`, // so the `Ty` itself needs a different one. id = self.next_id(); - hir::TyTraitObject(hir_vec![principal], self.elided_lifetime(span)) + hir::TyTraitObject(hir_vec![principal], self.elided_dyn_bound(span)) } else { hir::TyPath(hir::QPath::Resolved(None, path)) } } - _ => hir::TyPath(qpath) + _ => hir::TyPath(qpath), }; - P(hir::Ty { id: id.node_id, hir_id: id.hir_id, node, span }) + P(hir::Ty { + id: id.node_id, + hir_id: id.hir_id, + node, + span, + }) + } + + /// Invoked to create the lifetime argument for a type `&T` + /// with no explicit lifetime. + fn elided_ref_lifetime(&mut self, span: Span) -> hir::Lifetime { + match self.anonymous_lifetime_mode { + // Intercept when we are in an impl header and introduce an in-band lifetime. + // Hence `impl Foo for &u32` becomes `impl<'f> Foo for &'f u32` for some fresh + // `'f`. + AnonymousLifetimeMode::CreateParameter => { + let fresh_name = self.collect_fresh_in_band_lifetime(span); + hir::Lifetime { + id: self.next_id().node_id, + span, + name: fresh_name, + } + } + + AnonymousLifetimeMode::PassThrough => self.new_implicit_lifetime(span), + } } - fn elided_lifetime(&mut self, span: Span) -> hir::Lifetime { + /// Invoked to create the lifetime argument(s) for a path like + /// `std::cell::Ref<T>`; note that implicit lifetimes in these + /// sorts of cases are deprecated. This may therefore report a warning or an + /// error, depending on the mode. + fn elided_path_lifetimes(&mut self, span: Span, count: usize) -> P<[hir::Lifetime]> { + match self.anonymous_lifetime_mode { + // NB. We intentionally ignore the create-parameter mode here + // and instead "pass through" to resolve-lifetimes, which will then + // report an error. This is because we don't want to support + // impl elision for deprecated forms like + // + // impl Foo for std::cell::Ref<u32> // note lack of '_ + AnonymousLifetimeMode::CreateParameter => {} + + // This is the normal case. + AnonymousLifetimeMode::PassThrough => {} + } + + (0..count) + .map(|_| self.new_implicit_lifetime(span)) + .collect() + } + + /// Invoked to create the lifetime argument(s) for an elided trait object + /// bound, like the bound in `Box<dyn Debug>`. This method is not invoked + /// when the bound is written, even if it is written with `'_` like in + /// `Box<dyn Debug + '_>`. In those cases, `lower_lifetime` is invoked. + fn elided_dyn_bound(&mut self, span: Span) -> hir::Lifetime { + match self.anonymous_lifetime_mode { + // NB. We intentionally ignore the create-parameter mode here. + // and instead "pass through" to resolve-lifetimes, which will apply + // the object-lifetime-defaulting rules. Elided object lifetime defaults + // do not act like other elided lifetimes. In other words, given this: + // + // impl Foo for Box<dyn Debug> + // + // we do not introduce a fresh `'_` to serve as the bound, but instead + // ultimately translate to the equivalent of: + // + // impl Foo for Box<dyn Debug + 'static> + // + // `resolve_lifetime` has the code to make that happen. + AnonymousLifetimeMode::CreateParameter => {} + + // This is the normal case. + AnonymousLifetimeMode::PassThrough => {} + } + + self.new_implicit_lifetime(span) + } + + fn new_implicit_lifetime(&mut self, span: Span) -> hir::Lifetime { hir::Lifetime { id: self.next_id().node_id, span, @@ -3713,9 +4229,11 @@ impl<'a> LoweringContext<'a> { fn maybe_lint_bare_trait(&self, span: Span, id: NodeId, is_global: bool) { if self.sess.features_untracked().dyn_trait { self.sess.buffer_lint_with_diagnostic( - builtin::BARE_TRAIT_OBJECT, id, span, + builtin::BARE_TRAIT_OBJECT, + id, + span, "trait objects without an explicit `dyn` are deprecated", - builtin::BuiltinLintDiagnostics::BareTraitObject(span, is_global) + builtin::BuiltinLintDiagnostics::BareTraitObject(span, is_global), ) } } diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index 12b472a7285..be8cceb6118 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -203,9 +203,31 @@ pub struct Lifetime { #[derive(Debug, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)] pub enum LifetimeName { + /// User typed nothing. e.g. the lifetime in `&u32`. Implicit, + + /// User typed `'_`. Underscore, + + /// Synthetic name generated when user elided a lifetime in an impl header, + /// e.g. the lifetimes in cases like these: + /// + /// impl Foo for &u32 + /// impl Foo<'_> for u32 + /// + /// in that case, we rewrite to + /// + /// impl<'f> Foo for &'f u32 + /// impl<'f> Foo<'f> for u32 + /// + /// where `'f` is something like `Fresh(0)`. The indices are + /// unique per impl, but not necessarily continuous. + Fresh(usize), + + /// User wrote `'static` Static, + + /// Some user-given name like `'x` Name(Name), } @@ -214,7 +236,7 @@ impl LifetimeName { use self::LifetimeName::*; match *self { Implicit => keywords::Invalid.name(), - Underscore => keywords::UnderscoreLifetime.name(), + Fresh(_) | Underscore => keywords::UnderscoreLifetime.name(), Static => keywords::StaticLifetime.name(), Name(name) => name, } @@ -235,7 +257,13 @@ impl Lifetime { use self::LifetimeName::*; match self.name { Implicit | Underscore => true, - Static | Name(_) => false, + + // It might seem surprising that `Fresh(_)` counts as + // *not* elided -- but this is because, as far as the code + // in the compiler is concerned -- `Fresh(_)` variants act + // equivalently to "some fresh name". They correspond to + // early-bound regions on an impl, in other words. + Fresh(_) | Static | Name(_) => false, } } diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs index 774b1442b71..c3b3e10201f 100644 --- a/src/librustc/ich/impls_hir.rs +++ b/src/librustc/ich/impls_hir.rs @@ -145,6 +145,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for hir::ImplItemId { impl_stable_hash_for!(enum hir::LifetimeName { Implicit, Underscore, + Fresh(index), Static, Name(name) }); diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs index 0aa750aba06..ceda72dcd7a 100644 --- a/src/librustc/middle/resolve_lifetime.rs +++ b/src/librustc/middle/resolve_lifetime.rs @@ -31,6 +31,7 @@ use syntax::ptr::P; use syntax_pos::Span; use errors::DiagnosticBuilder; use util::nodemap::{DefIdMap, FxHashMap, FxHashSet, NodeMap, NodeSet}; +use session::Session; use std::slice; use rustc::lint; @@ -468,11 +469,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { fn visit_item(&mut self, item: &'tcx hir::Item) { match item.node { hir::ItemFn(ref decl, _, _, _, ref generics, _) => { - self.visit_early_late(None, - decl, - generics, - |this| { - intravisit::walk_item(this, item); + self.visit_early_late(None, decl, generics, |this| { + intravisit::walk_item(this, item); }); } @@ -505,7 +503,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } else { 0 }; - let lifetimes = generics.lifetimes() + let lifetimes = generics + .lifetimes() .map(|def| Region::early(&self.tcx.hir, &mut index, def)) .collect(); let next_early_index = index + generics.ty_params().count() as u32; @@ -526,12 +525,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem) { match item.node { hir::ForeignItemFn(ref decl, _, ref generics) => { - self.visit_early_late(None, - decl, - generics, - |this| { - intravisit::walk_foreign_item(this, item); - }) + self.visit_early_late(None, decl, generics, |this| { + intravisit::walk_foreign_item(this, item); + }) } hir::ForeignItemStatic(..) => { intravisit::walk_foreign_item(self, item); @@ -586,7 +582,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { // cc #48468 self.resolve_elided_lifetimes(slice::from_ref(lifetime), false) } - LifetimeName::Static | LifetimeName::Name(_) => { + LifetimeName::Fresh(_) | LifetimeName::Static | LifetimeName::Name(_) => { // If the user wrote an explicit name, use that. self.visit_lifetime(lifetime); } @@ -670,7 +666,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { if let Some(elision_region) = elision { let scope = Scope::Elision { elide: Elide::Exact(elision_region), - s: self.scope + s: self.scope, }; self.with(scope, |_old_scope, this| { let scope = Scope::Binder { @@ -716,12 +712,13 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { &trait_item.generics, |this| intravisit::walk_trait_item(this, trait_item), ); - }, + } Type(ref bounds, ref ty) => { let generics = &trait_item.generics; let mut index = self.next_early_index(); debug!("visit_ty: index = {}", index); - let lifetimes = generics.lifetimes() + let lifetimes = generics + .lifetimes() .map(|lt_def| Region::early(&self.tcx.hir, &mut index, lt_def)) .collect(); @@ -741,12 +738,12 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { this.visit_ty(ty); } }); - }, + } Const(_, _) => { // Only methods and types support generics. assert!(trait_item.generics.params.is_empty()); intravisit::walk_trait_item(self, trait_item); - }, + } } } @@ -761,12 +758,13 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { &impl_item.generics, |this| intravisit::walk_impl_item(this, impl_item), ) - }, + } Type(ref ty) => { let generics = &impl_item.generics; let mut index = self.next_early_index(); debug!("visit_ty: index = {}", index); - let lifetimes = generics.lifetimes() + let lifetimes = generics + .lifetimes() .map(|lt_def| Region::early(&self.tcx.hir, &mut index, lt_def)) .collect(); @@ -781,12 +779,12 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { this.visit_generics(generics); this.visit_ty(ty); }); - }, + } Const(_, _) => { // Only methods and types support generics. assert!(impl_item.generics.params.is_empty()); intravisit::walk_impl_item(self, impl_item); - }, + } } } @@ -822,7 +820,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { fn visit_generics(&mut self, generics: &'tcx hir::Generics) { check_mixed_explicit_and_in_band_defs( self.tcx, - &generics.lifetimes().cloned().collect::<Vec<_>>() + &generics.lifetimes().cloned().collect::<Vec<_>>(), ); for ty_param in generics.ty_params() { walk_list!(self, visit_ty_param_bound, &ty_param.bounds); @@ -842,7 +840,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { self.trait_ref_hack = true; let next_early_index = self.next_early_index(); let scope = Scope::Binder { - lifetimes: bound_generic_params.lifetimes() + lifetimes: bound_generic_params + .lifetimes() .map(|def| Region::late(&self.tcx.hir, def)) .collect(), s: self.scope, @@ -890,8 +889,11 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { ) { debug!("visit_poly_trait_ref trait_ref={:?}", trait_ref); - if !self.trait_ref_hack || - trait_ref.bound_generic_params.iter().any(|p| p.is_lifetime_param()) + if !self.trait_ref_hack + || trait_ref + .bound_generic_params + .iter() + .any(|p| p.is_lifetime_param()) { if self.trait_ref_hack { span_err!( @@ -903,7 +905,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } let next_early_index = self.next_early_index(); let scope = Scope::Binder { - lifetimes: trait_ref.bound_generic_params + lifetimes: trait_ref + .bound_generic_params .lifetimes() .map(|def| Region::late(&self.tcx.hir, def)) .collect(), @@ -1144,7 +1147,8 @@ fn compute_object_lifetime_defaults( .map(|set| match *set { Set1::Empty => "BaseDefault".to_string(), Set1::One(Region::Static) => "'static".to_string(), - Set1::One(Region::EarlyBound(i, _, _)) => generics.lifetimes() + Set1::One(Region::EarlyBound(i, _, _)) => generics + .lifetimes() .nth(i as usize) .unwrap() .lifetime @@ -1182,7 +1186,8 @@ fn object_lifetime_defaults_for_item( } } - generics.ty_params() + generics + .ty_params() .map(|param| { let mut set = Set1::Empty; @@ -1278,17 +1283,21 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { if let hir::map::NodeLifetime(hir_lifetime) = this.tcx.hir.get(node_id) { let span = hir_lifetime.span; let id = hir_lifetime.id; - debug!("id ={:?} span = {:?} hir_lifetime = {:?}", - node_id, - span, - hir_lifetime); + debug!( + "id ={:?} span = {:?} hir_lifetime = {:?}", + node_id, span, hir_lifetime + ); this.tcx - .struct_span_lint_node(lint::builtin::SINGLE_USE_LIFETIME, - id, - span, - &format!("lifetime name `{}` only used once", - hir_lifetime.name.name())) + .struct_span_lint_node( + lint::builtin::SINGLE_USE_LIFETIME, + id, + span, + &format!( + "lifetime name `{}` only used once", + hir_lifetime.name.name() + ), + ) .emit(); } } @@ -1379,8 +1388,10 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { next_early_index, abstract_type_parent, .. - } if (!only_abstract_type_parent || abstract_type_parent) - => return next_early_index, + } if (!only_abstract_type_parent || abstract_type_parent) => + { + return next_early_index + } Scope::Binder { s, .. } | Scope::Body { s, .. } @@ -1698,8 +1709,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { } // Foreign functions, `fn(...) -> R` and `Trait(...) -> R` (both types and bounds). - hir::map::NodeForeignItem(_) | hir::map::NodeTy(_) | hir::map::NodeTraitRef(_) => - None, + hir::map::NodeForeignItem(_) | hir::map::NodeTy(_) | hir::map::NodeTraitRef(_) => None, // Everything else (only closures?) doesn't // actually enjoy elision in return types. _ => { @@ -1894,7 +1904,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { lint::builtin::ELIDED_LIFETIME_IN_PATH, id, span, - &format!("hidden lifetime parameters are deprecated, try `Foo<'_>`")) + &format!("hidden lifetime parameters are deprecated, try `Foo<'_>`"), + ) .emit(); } let error = loop { @@ -1933,25 +1944,14 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { } }; - let mut err = struct_span_err!( - self.tcx.sess, - span, - E0106, - "missing lifetime specifier{}", - if lifetime_refs.len() > 1 { "s" } else { "" } - ); - let msg = if lifetime_refs.len() > 1 { - format!("expected {} lifetime parameters", lifetime_refs.len()) - } else { - format!("expected lifetime parameter") - }; - err.span_label(span, msg); + let mut err = report_missing_lifetime_specifiers(self.tcx.sess, span, lifetime_refs.len()); if let Some(params) = error { if lifetime_refs.len() == 1 { self.report_elision_failure(&mut err, params); } } + err.emit(); } @@ -2086,7 +2086,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { ); err.emit(); } - hir::LifetimeName::Implicit | hir::LifetimeName::Name(_) => {} + hir::LifetimeName::Fresh(_) | hir::LifetimeName::Implicit | + hir::LifetimeName::Name(_) => {} } } @@ -2138,7 +2139,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { )) .emit(); } - hir::LifetimeName::Implicit | hir::LifetimeName::Name(_) => { + hir::LifetimeName::Fresh(_) | hir::LifetimeName::Implicit | + hir::LifetimeName::Name(_) => { self.resolve_lifetime_ref(bound); } } @@ -2146,9 +2148,11 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { } } - fn check_lifetime_def_for_shadowing(&self, - mut old_scope: ScopeRef, - lifetime: &'tcx hir::Lifetime) { + fn check_lifetime_def_for_shadowing( + &self, + mut old_scope: ScopeRef, + lifetime: &'tcx hir::Lifetime, + ) { for &(label, label_span) in &self.labels_in_fn { // FIXME (#24278): non-hygienic comparison if lifetime.name.name() == label { @@ -2216,14 +2220,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { self.map.defs.insert(lifetime_ref.id, def); match def { - Region::LateBoundAnon(..) | - Region::Static => { + Region::LateBoundAnon(..) | Region::Static => { // These are anonymous lifetimes or lifetimes that are not declared. } - Region::Free(_, def_id) | - Region::LateBound(_, def_id, _) | - Region::EarlyBound(_, def_id, _) => { + Region::Free(_, def_id) + | Region::LateBound(_, def_id, _) + | Region::EarlyBound(_, def_id, _) => { // A lifetime declared by the user. if !self.lifetime_uses.contains_key(&def_id) { self.lifetime_uses @@ -2255,8 +2258,7 @@ fn insert_late_bound_lifetimes( ) { debug!( "insert_late_bound_lifetimes(decl={:?}, generics={:?})", - decl, - generics + decl, generics ); let mut constrained_by_input = ConstrainedCollector { @@ -2335,8 +2337,7 @@ fn insert_late_bound_lifetimes( debug!( "insert_late_bound_lifetimes: \ lifetime {:?} with id {:?} is late-bound", - lifetime.lifetime.name, - lifetime.lifetime.id + lifetime.lifetime.name, lifetime.lifetime.id ); let inserted = map.late_bound.insert(lifetime.lifetime.id); @@ -2403,3 +2404,27 @@ fn insert_late_bound_lifetimes( } } } + +pub fn report_missing_lifetime_specifiers( + sess: &Session, + span: Span, + count: usize, +) -> DiagnosticBuilder<'_> { + let mut err = struct_span_err!( + sess, + span, + E0106, + "missing lifetime specifier{}", + if count > 1 { "s" } else { "" } + ); + + let msg = if count > 1 { + format!("expected {} lifetime parameters", count) + } else { + format!("expected lifetime parameter") + }; + + err.span_label(span, msg); + + err +} diff --git a/src/test/ui/feature-gate-in_band_lifetimes-impl.rs b/src/test/ui/feature-gate-in_band_lifetimes-impl.rs new file mode 100644 index 00000000000..a02b3e80009 --- /dev/null +++ b/src/test/ui/feature-gate-in_band_lifetimes-impl.rs @@ -0,0 +1,22 @@ +// Copyright 2017 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![allow(warnings)] +#![feature(underscore_lifetimes)] + +trait MyTrait<'a> { } + +impl<'a> MyTrait<'a> for &u32 { } +//~^ ERROR missing lifetime specifier + +impl<'a> MyTrait<'_> for &'a f32 { } +//~^ ERROR missing lifetime specifier + +fn main() {} diff --git a/src/test/ui/feature-gate-in_band_lifetimes-impl.stderr b/src/test/ui/feature-gate-in_band_lifetimes-impl.stderr new file mode 100644 index 00000000000..e32a06c3ce4 --- /dev/null +++ b/src/test/ui/feature-gate-in_band_lifetimes-impl.stderr @@ -0,0 +1,15 @@ +error[E0106]: missing lifetime specifier + --> $DIR/feature-gate-in_band_lifetimes-impl.rs:16:26 + | +LL | impl<'a> MyTrait<'a> for &u32 { } + | ^ expected lifetime parameter + +error[E0106]: missing lifetime specifier + --> $DIR/feature-gate-in_band_lifetimes-impl.rs:19:18 + | +LL | impl<'a> MyTrait<'_> for &'a f32 { } + | ^^ expected lifetime parameter + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0106`. diff --git a/src/test/ui/in-band-lifetimes/impl/assoc-type.rs b/src/test/ui/in-band-lifetimes/impl/assoc-type.rs new file mode 100644 index 00000000000..54f38b2e729 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/assoc-type.rs @@ -0,0 +1,38 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Test that we do not yet support elision in associated types, even +// when there is just one name we could take from the impl header. + +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait { + type Output; +} + +impl MyTrait for &i32 { + type Output = &i32; + //~^ ERROR missing lifetime specifier +} + +impl MyTrait for &u32 { + type Output = &'_ i32; + //~^ ERROR missing lifetime specifier +} + +// This is what you have to do: +impl MyTrait for &'a f32 { + type Output = &'a f32; +} + +fn main() { } diff --git a/src/test/ui/in-band-lifetimes/impl/assoc-type.stderr b/src/test/ui/in-band-lifetimes/impl/assoc-type.stderr new file mode 100644 index 00000000000..909b86daef0 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/assoc-type.stderr @@ -0,0 +1,15 @@ +error[E0106]: missing lifetime specifier + --> $DIR/assoc-type.rs:24:19 + | +LL | type Output = &i32; + | ^ expected lifetime parameter + +error[E0106]: missing lifetime specifier + --> $DIR/assoc-type.rs:29:20 + | +LL | type Output = &'_ i32; + | ^^ expected lifetime parameter + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0106`. diff --git a/src/test/ui/in-band-lifetimes/impl/dyn-trait.rs b/src/test/ui/in-band-lifetimes/impl/dyn-trait.rs new file mode 100644 index 00000000000..e839248b0e3 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/dyn-trait.rs @@ -0,0 +1,45 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Test that `impl MyTrait<'_> for &i32` is equivalent to `impl<'a, +// 'b> MyTrait<'a> for &'b i32`. + +#![allow(warnings)] + +#![feature(dyn_trait)] +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +use std::fmt::Debug; + +// Equivalent to `Box<dyn Debug + 'static>`: +trait StaticTrait { } +impl StaticTrait for Box<dyn Debug> { } + +// Equivalent to `Box<dyn Debug + 'static>`: +trait NotStaticTrait { } +impl NotStaticTrait for Box<dyn Debug + '_> { } + +fn static_val<T: StaticTrait>(_: T) { +} + +fn with_dyn_debug_static<'a>(x: Box<dyn Debug + 'a>) { + static_val(x); //~ ERROR cannot infer +} + +fn not_static_val<T: NotStaticTrait>(_: T) { +} + +fn with_dyn_debug_not_static<'a>(x: Box<dyn Debug + 'a>) { + not_static_val(x); // OK +} + +fn main() { +} diff --git a/src/test/ui/in-band-lifetimes/impl/dyn-trait.stderr b/src/test/ui/in-band-lifetimes/impl/dyn-trait.stderr new file mode 100644 index 00000000000..0054ca3d1a5 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/dyn-trait.stderr @@ -0,0 +1,22 @@ +error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements + --> $DIR/dyn-trait.rs:34:16 + | +LL | static_val(x); //~ ERROR cannot infer + | ^ + | +note: first, the lifetime cannot outlive the lifetime 'a as defined on the function body at 33:1... + --> $DIR/dyn-trait.rs:33:1 + | +LL | fn with_dyn_debug_static<'a>(x: Box<dyn Debug + 'a>) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: ...so that the expression is assignable: + expected std::boxed::Box<std::fmt::Debug> + found std::boxed::Box<std::fmt::Debug + 'a> + = note: but, the lifetime must be valid for the static lifetime... + = note: ...so that the types are compatible: + expected StaticTrait + found StaticTrait + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0495`. diff --git a/src/test/ui/in-band-lifetimes/impl/path-elided.rs b/src/test/ui/in-band-lifetimes/impl/path-elided.rs new file mode 100644 index 00000000000..fa1b4523889 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/path-elided.rs @@ -0,0 +1,23 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait { } + +struct Foo<'a> { x: &'a u32 } + +impl MyTrait for Foo { + //~^ ERROR missing lifetime specifier +} + +fn main() {} diff --git a/src/test/ui/in-band-lifetimes/impl/path-elided.stderr b/src/test/ui/in-band-lifetimes/impl/path-elided.stderr new file mode 100644 index 00000000000..19e69c61a03 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/path-elided.stderr @@ -0,0 +1,9 @@ +error[E0106]: missing lifetime specifier + --> $DIR/path-elided.rs:19:18 + | +LL | impl MyTrait for Foo { + | ^^^ expected lifetime parameter + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0106`. diff --git a/src/test/ui/in-band-lifetimes/impl/path-underscore.rs b/src/test/ui/in-band-lifetimes/impl/path-underscore.rs new file mode 100644 index 00000000000..56f2d93d9e0 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/path-underscore.rs @@ -0,0 +1,47 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Test that `impl MyTrait for Foo<'_>` works. + +// run-pass + +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait { } + +struct Foo<'a> { x: &'a u32 } + +impl MyTrait for Foo<'_> { +} + +fn impls_my_trait<T: MyTrait>() { } + +fn impls_my_trait_val<T: MyTrait>(_: T) { + impls_my_trait::<T>(); +} + +fn random_where_clause() +where for<'a> Foo<'a>: MyTrait { } + +fn main() { + let x = 22; + let f = Foo { x: &x }; + + // This type is `Foo<'x>` for a local lifetime `'x`; so the impl + // must apply to any lifetime to apply to this. + impls_my_trait_val(f); + + impls_my_trait::<Foo<'static>>(); + + random_where_clause(); +} diff --git a/src/test/ui/in-band-lifetimes/impl/ref-underscore.rs b/src/test/ui/in-band-lifetimes/impl/ref-underscore.rs new file mode 100644 index 00000000000..1b1035abeba --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/ref-underscore.rs @@ -0,0 +1,43 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Test that `impl MyTrait for &i32` works and is equivalent to any lifetime. + +// run-pass + +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait { } + +impl MyTrait for &i32 { +} + +fn impls_my_trait<T: MyTrait>() { } + +fn impls_my_trait_val<T: MyTrait>(_: T) { + impls_my_trait::<T>(); +} + +fn random_where_clause() +where for<'a> &'a i32: MyTrait { } + +fn main() { + let x = 22; + let f = &x; + + impls_my_trait_val(f); + + impls_my_trait::<&'static i32>(); + + random_where_clause(); +} diff --git a/src/test/ui/in-band-lifetimes/impl/trait-elided.rs b/src/test/ui/in-band-lifetimes/impl/trait-elided.rs new file mode 100644 index 00000000000..7594d66e078 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/trait-elided.rs @@ -0,0 +1,21 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait<'a> { } + +impl MyTrait for u32 { + //~^ ERROR missing lifetime specifier +} + +fn main() {} diff --git a/src/test/ui/in-band-lifetimes/impl/trait-elided.stderr b/src/test/ui/in-band-lifetimes/impl/trait-elided.stderr new file mode 100644 index 00000000000..bb301882868 --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/trait-elided.stderr @@ -0,0 +1,9 @@ +error[E0106]: missing lifetime specifier + --> $DIR/trait-elided.rs:17:6 + | +LL | impl MyTrait for u32 { + | ^^^^^^^ expected lifetime parameter + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0106`. diff --git a/src/test/ui/in-band-lifetimes/impl/trait-underscore.rs b/src/test/ui/in-band-lifetimes/impl/trait-underscore.rs new file mode 100644 index 00000000000..077e33c1efd --- /dev/null +++ b/src/test/ui/in-band-lifetimes/impl/trait-underscore.rs @@ -0,0 +1,48 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Test that `impl MyTrait<'_> for &i32` is equivalent to `impl<'a, +// 'b> MyTrait<'a> for &'b i32`. +// +// run-pass + +#![allow(warnings)] + +#![feature(in_band_lifetimes)] +#![feature(underscore_lifetimes)] + +trait MyTrait<'a> { } + +// This is equivalent to `MyTrait<'a> for &'b i32`, which is proven by +// the code below. +impl MyTrait<'_> for &i32 { +} + +// When called, T will be `&'x i32` for some `'x`, so since we can +// prove that `&'x i32: for<'a> MyTrait<'a>, then we know that the +// lifetime parameter above is disconnected. +fn impls_my_trait<T: for<'a> MyTrait<'a>>() { } + +fn impls_my_trait_val<T: for<'a> MyTrait<'a>>(_: T) { + impls_my_trait::<T>(); +} + +fn random_where_clause() +where for<'a, 'b> &'a i32: MyTrait<'b> { } + +fn main() { + let x = 22; + let f = &x; + impls_my_trait_val(f); + + impls_my_trait::<&'static i32>(); + + random_where_clause(); +} diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.rs b/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.rs new file mode 100644 index 00000000000..d10541ad33b --- /dev/null +++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.rs @@ -0,0 +1,26 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Check that the `'_` in `dyn Trait + '_` acts like ordinary elision, +// and not like an object lifetime default. +// +// cc #48468 + +#![feature(dyn_trait)] +#![feature(underscore_lifetimes)] + +use std::fmt::Debug; + +struct Foo { + x: Box<dyn Debug + '_>, //~ ERROR missing lifetime specifier + //~^ ERROR E0228 +} + +fn main() { } diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.stderr b/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.stderr new file mode 100644 index 00000000000..a88ecb18dd6 --- /dev/null +++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore-in-struct.stderr @@ -0,0 +1,16 @@ +error[E0106]: missing lifetime specifier + --> $DIR/dyn-trait-underscore-in-struct.rs:22:24 + | +LL | x: Box<dyn Debug + '_>, //~ ERROR missing lifetime specifier + | ^^ expected lifetime parameter + +error[E0228]: the lifetime bound for this object type cannot be deduced from context; please supply an explicit bound + --> $DIR/dyn-trait-underscore-in-struct.rs:22:12 + | +LL | x: Box<dyn Debug + '_>, //~ ERROR missing lifetime specifier + | ^^^^^^^^^^^^^^ + +error: aborting due to 2 previous errors + +Some errors occurred: E0106, E0228. +For more information about an error, try `rustc --explain E0106`. |